The evolutionary dynamics of local infection and global reproduction in host–parasite interactions

Abstract

A fundamental question in both evolutionary biology and parasitology is why do different levels of virulence evolve in different parasites. Here we use explicitly spatial lattice models to show how the spatial relationships of infection and host reproduction determine the degree of virulence that will occur. When the reproduction of the host acts over larger spatial scales than the infection process higher virulence is predicted. In contrast to both the mean‐field and the case where infection acts over larger spatial scales than reproduction, the transmission and virulence predicted are always finite as “self‐shading” of infected individuals always occurs. This process may help to explain the evolution of the high virulence of larval diseases of insects where reproduction clearly acts over greater distances than infection.