Title: "Sexual Selection, Structured Populations and the Evolution of Social Behaviour" 

Date Friday 26 Janury 2018
Venue Heriot-Watt, Room MB1.62
Time 3.15PM

Speaker: Mark Schaffer (Heriot-Watt University) – joint work with David R. Pugh (Oxford) and Paul Seabright (Toulouse)


This paper models the co-evolution by natural selection of an individually costly co-operative behaviour trait together with a preference for social partners who bear that trait. Under sexual reproduction population structure - the non-random association of individuals within a population - co-evolves with behavioural traits that are not individually adaptive but whose bearers face enhanced reproduction prospects due to the structure. It is well known that cooperation can be favoured by natural selection if cooperators are likely to associate with other cooperators. In this paper we use insights from sexual selection to endogenize the mechanisms of association, characterized in terms of general properties of matching functions. We derive conditions for the existence of multiple stable monomorphic equilibria and also for balanced polymorphic equilibria in which different behavioural traits coexist. Such equilibria can support not only mutual cooperation, but also hierarchies in which cooperators are exploited by others.