Waiting for volunteers

  • CL_25Exh_Rm115 Monash University Clayton Clayton Australia

Speaker: Dr. Jorge Peña - Geomar

In many natural systems, group formation processes lead to a dependence of the
group size distribution on the level of cooperation in the population. Examples include social microbes producing adhesive proteins, bark beetles attacking host trees, burying beetles preparing and burying carcasses, and social carnivores participating in collective hunting or confrontational scavenging. Here, we explore the evolutionary consequences of endogenous group formation in a prominent model of social evolution: the volunteer’s dilemma. In our variant of the model, individuals are sequentially recruited by focal
groups until the critical number of cooperators needed to provide a collective good is reached. This rule of group formation generates predictions that are in stark contrast to those resulting from the standard volunteer’s dilemma with constant group size. In particular, protected polymorphisms are impossible and the invasion barrier for cooperator mutants can be less severe at sufficiently low cost-to-benefit ratios. Our results highlight the importance of explicitly accounting for endogenous processes of group formation in models of social evolution.