Phenotype affinity mediated interactions can facilitate the evolution of cooperation

TL;DR

This study explores how phenotype-mediated interaction rates influence the evolution of cooperation, revealing that low-cost phenotype expression can promote cooperation by modulating interaction dynamics in the Prisoner's Dilemma.

Contribution

It introduces a model where phenotype diversity affects interaction rates and demonstrates how low-cost phenotype expression can favor cooperative behavior over defectors.

Findings

Low-cost phenotype expression promotes cooperation.

Diversity of phenotypes can destabilize due to mutant invasion.

Cooperation and phenotype diversity can mutually reinforce each other.

Abstract

We study the coevolutionary dynamics of the diversity of phenotype expression and the evolution of cooperation in the Prisoner's Dilemma game. Rather than pre-assigning zero-or-one interaction rate, we diversify the rate of interaction by associating it with the phenotypes shared in common. Individuals each carry a set of potentially expressible phenotypes and expresses a certain number of phenotypes at a cost proportional to the number. The number of expressed phenotypes and thus the rate of interaction is an evolvable trait. Our results show that nonnegligible cost of expressing phenotypes restrains phenotype expression, and the evolutionary race mainly proceeds on between cooperative strains and defective strains who express a very few phenotypes. It pays for cooperative strains to express a very few phenotypes. Though such a low level of expression weakens reciprocity between cooperative strains, it decelerates rate of interaction between cooperative strains and defective strains to a larger degree, leading to the predominance of cooperative strains over defective strains. We also find that evolved diversity of phenotype expression can occasionally destabilize due to the invasion of defective mutants, implying that cooperation and diversity of phenotype expression can mutually reinforce each other. Therefore, our results provide new insights into better understanding the coevolution of cooperation and the diversity of phenotype expression.