Invasion of cooperative parasites in moderately structured host populations

TL;DR

This paper investigates how the spatial structure of host populations influences the likelihood of cooperative parasites invading, highlighting the critical population scale where invasion becomes probable.

Contribution

It introduces a model analyzing invasion probabilities of cooperative parasites in moderately structured populations with spatial considerations.

Findings

Invasion likelihood depends on the spatial scale of host population structure.

Identifies a critical spatial scale where invasion shifts from unlikely to likely.

Provides analytical insights into parasite invasion dynamics in structured populations.

Abstract

Certain defense mechanisms of phages against the immune system of their bacterial host rely on cooperation of phages. Motivated by this example we analyse invasion probabilities of cooperative parasites in host populations that are moderately structured. More precisely we assume that hosts are arranged on the vertices of a configuration model and that offspring of parasites move to nearest neighbours sites to infect new hosts. We consider parasites that generate many offspring at reproduction, but do this (usually) only when infecting a host simultaneously. In this regime we identify and analyse the spatial scale of the population structure at which invasion of parasites turns from being an unlikely to an highly probable event.