Eco-evolutionary dynamics of social dilemmas

TL;DR

This paper explores how ecological fluctuations and non-linear social interactions influence the evolution of cooperation, revealing complex dynamics that help maintain cooperation at high densities in changing environments.

Contribution

It introduces a model analyzing eco-evolutionary feedbacks in non-linear social dilemmas with fluctuating populations and environments, highlighting complex dynamics.

Findings

Ecological fluctuations support high-density cooperation.

Complex dynamics emerge from eco-evolutionary feedbacks.

Non-linear interactions influence cooperation stability.

Abstract

Social dilemmas are an integral part of social interactions. Cooperative actions, ranging from secreting extra-cellular products in microbial populations to donating blood in humans, are costly to the actor and hence create an incentive to shirk and avoid the costs. Nevertheless, cooperation is ubiquitous in nature. Both costs and benefits often depend non-linearly on the number and types of individuals involved -- as captured by idioms such as `too many cooks spoil the broth' where additional contributions are discounted, or `two heads are better than one' where cooperators synergistically enhance the group benefit. Interaction group sizes may depend on the size of the population and hence on ecological processes. This results in feedback mechanisms between ecological and evolutionary processes, which jointly affect and determine the evolutionary trajectory. Only recently combined eco-evolutionary processes became experimentally tractable in microbial social dilemmas. Here we analyse the evolutionary dynamics of non-linear social dilemmas in settings where the population fluctuates in size and the environment changes over time. In particular, cooperation is often supported and maintained at high densities through ecological fluctuations. Moreover, we find that the combination of the two processes routinely reveals highly complex dynamics, which suggests common occurrence in nature.