Moderate Contact between Sub-populations Promotes Evolved Assortativity Enabling Group Selection

Abstract

Abstract. Group selection is easily observed when spatial group structure is imposed on a population. In fact, spatial structure is just a means of providing assortative interactions such that the benefits of cooperating are delivered to other cooperators more than to selfish individuals. In principle, assortative interactions could be supported by individually adapted traits without physical grouping. But this possibility seems to be ruled-out because any 'marker' that cooperators used for this purpose could be adopted by selfish individuals also. However, here we show that stable assortative marking can evolve when sub-populations at different evolutionarily stable strategies (ESSs) are brought into contact. Interestingly, if they are brought into contact too quickly, individual selection causes loss of behavioural diversity before assortative markers have a chance to evolve. But if they are brought into contact slowly, moderate initial mixing between sub-populations produces a pressure to evolve traits that facilitate assortative interactions. Once assortative interactions have become established, group competition between the two ESSs is facilitated without any spatial group structure. This process thus illustrates conditions where individual selection canalises groups that are initially spatially defined into stable groups that compete without the need for continued spatial separation.

Evolutionary Connectionism: Algorithmic Principles Underlying the Evolution of Biological Organisation in Evo-Devo, Evo-Eco and Evolutionary Transitions

“…the relevant evolutionary unit is now the pair. Putting together the ideas of social niche construction with a minimal demonstration of the between-group selection it enables, we show that individual selection creates groups that facilitate higher-level adaptation (Snowdon et al 2011). This is analogous to the jumps in configuration space that are facilitated by the new units in deep optimisation.…”

Can Selfish Symbioses Effect Higher-Level Selection?

“…In contrast, we are interested in scenarios where individually selected traits affect the strength of group selection or create group selection de novo ( 6). For example, related work addresses the evolution of individually specified traits that affect group size ( 7,8), or the evolution of markers that influence behavioural grouping ( 9). Here we address a multi-species scenario where species can evolve symbiotic relationships that allow explicit control over whether they group and who they group with.…”