Economic game theory for mutualism and cooperation

	Economic game theory for mutualism and cooperation
	Archetti M 1,2; Scheuring I 3; Yu DW6,7; Hoffman M 4; Frederickson ME 5; Pierce NE1; archetti.marco@googlemail.com ; npierce@oeb.harvard.edu ; dougwyu@gmail.com
	2011
发表期刊	ECOLOGY LETTERS
卷号	14 期号:12 页码:1300-1312
合作性质	其它
摘要	We review recent work at the interface of economic game theory and evolutionary biology that provides new insights into the evolution of partner choice, host sanctions, partner fidelity feedback and public goods. (1) The theory of games with asymmetrical information shows that the right incentives allow hosts to screen-out parasites and screen-in mutualists, explaining successful partner choice in the absence of signalling. Applications range from ant-plants to microbiomes. (2) Contract theory distinguishes two longstanding but weakly differentiated explanations of host response to defectors: host sanctions and partner fidelity feedback. Host traits that selectively punish misbehaving symbionts are parsimoniously interpreted as pre-adaptations. Yucca-moth and legume-rhizobia mutualisms are argued to be examples of partner fidelity feedback. (3) The theory of public goods shows that cooperation in multi-player interactions can evolve in the absence of assortment, in one-shot social dilemmas among non-kin. Applications include alarm calls in vertebrates and exoenzymes in microbes.
关键词	Coevolution Common-pool Resource Cooperation Game Theory Host Sanctions Mutualism
资助者	Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia.
收录类别	SCI
语种	英语
资助者	Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia. ; Our support came from the National Science Foundation (SES-0750480) and the European Science Foundation⁄European Collaborative Research (ESF⁄EURO- CORES) programme on The Evolution of Cooperation and Trading (TECT) project BIOCONTRACT, founded by R. Noe ¨ and P. Hammerstein. We also received support from OTKA Hungary (T049692 and NN71700), the European Union Marie Curie Fellow- ship programme, Yunnan Province (20080A001), the Chinese Academy of Sciences (0902281081, KSCX2-YW-Z-1027, Y002731079), the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant program, the UK Medical Research Council Milstein Award (G0801721), and the University of East Anglia.
文献类型	期刊论文
条目标识符	http://ir.kiz.ac.cn/handle/152453/10401
专题	科研部门_生态学与环境保护中心（俞维理）遗传资源与进化国家重点实验室
通讯作者	archetti.marco@googlemail.com; npierce@oeb.harvard.edu; dougwyu@gmail.com
作者单位	1.Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, 26 Oxford St., Harvard University, Cambridge, MA 02138, USA 2.Department of Business and Economics, University of Basel, Peter Merian-Weg 6, Basel 4002, Switzerland 3.Research Group of Theoretical Biology and Ecology, Department of Plant Taxonomy and Ecology, Eo ¨tvo ¨s University and HAS, Pa ´zma ´ny Pe ´ter se ´ta ´ny 1C, Budapest H-1117, Hungary 4.Rady School of Management, University of California, San Diego, Otterson Hall, 9500 Gilman Drive 0553, La Jolla, CA 92093, USA 5.Department of Ecology & Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, ON M5S3G5, Canada 6.Ecology, Conservation, and Environment Center (ECEC), State Key Laboratory of Genetic Resources and Evolution, 32 Jiaochang East Rd., Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China 7.School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR47TJ, UK
推荐引用方式 GB/T 7714	Archetti M,Scheuring I,Yu DW*,et al. Economic game theory for mutualism and cooperation[J]. ECOLOGY LETTERS,2011,14(12):1300-1312.
APA	Archetti M.,Scheuring I.,Yu DW*.,Hoffman M.,Frederickson ME.,...&dougwyu@gmail.com.(2011).Economic game theory for mutualism and cooperation.ECOLOGY LETTERS,14(12),1300-1312.
MLA	Archetti M,et al."Economic game theory for mutualism and cooperation".ECOLOGY LETTERS 14.12(2011):1300-1312.

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