The mode of host-parasite interaction shapes coevolutionary dynamics and the fate of host cooperation

TL;DR

This study uses stochastic models to explore how different host-parasite genetic interactions influence coevolution, population structure, and the persistence of cooperation in hosts, highlighting the importance of interaction mode.

Contribution

It demonstrates how the mode of host-parasite interaction affects coevolutionary dynamics and host cooperation, revealing that matching alleles promote cooperation.

Findings

Host cooperation is more stable with matching alleles (MA).

MA interactions cause bottlenecks that prevent defector invasion.

Migrant cooperators can invade defector populations under MA.

Abstract

Antagonistic coevolution between hosts and parasites can have a major impact on host population structures, and hence on the evolution of social traits. Using stochastic modelling techniques in the context of bacteria-virus interactions, we investigate the impact of coevolution across a continuum of host-parasite genetic specificity (specifically, where genotypes have the same infectivity/resistance ranges (matching alleles, MA) to highly variable ranges (gene-for-gene, GFG)) on population genetic structure, and on the social behaviour of the host. We find that host cooperation is more likely to be maintained towards the MA end of the continuum, as the more frequent bottlenecks associated with an MA-like interaction can prevent defector invasion, and can even allow migrant cooperators to invade populations of defectors.