The evolution of cooperation: Interacting phenotypes among social partners
University of Chicago Press
Reason for embargo
Models of cooperation among non-kin suggest that social assortment is important for the evolution of cooperation. Theory predicts interacting phenotypes, whereby an individual’s behaviour depends on the behaviour of its social partners, can drive such social assortment. We measured repeated indirect genetic effects (IGEs) during cooperative predator inspection in eight populations of Trinidadian guppies (Poecilia reticulata) that vary in their evolutionary history of predation. Four broad patterns emerged that were dependent on river, predation history, and sex: i. current partner behaviour had the largest effect on focal behaviour, with fish from low predation habitats responding more to their social partners than fish from high predation habitats, ii. different focal/partner behaviour combinations can generate cooperation, iii. some high predation fish exhibited carryover effects across social partners, and iv. high predation fish were more risk averse. These results provide the first large scale comparison of interacting phenotypes during cooperation across wild animal populations, highlighting the potential importance of IGEs in maintaining cooperation. Intriguingly whilst focal fish responded strongly to current social partners, carryover effects between social partners suggest generalised reciprocity (help anyone if helped by someone) may contribute to the evolution of cooperation in some, but not all, populations of guppies.
DPC and SKD acknowledge funding from the Leverhulme Trust (RPG-175 and ECF/2010/0672 respectively) and the Danish Council for Independent Research. BHB acknowledges funding from the National Science Foundation (NSF IOS: 1453536).
This is the author accepted manuscript. The final version is available from University of Chicago Press via the DOI in this record.
Published online 31 March 2017