Selection of Intermediate Rates of Increase in Parasite-Host Systems

Abstract

Parasite-host systems are ideal candidates for interdemic or group selection because of the potential for selection for avirulence based upon reduced host (hence group) survival. Such selection may have been an important ingredient in the stabilization of the myxomatosis-rabbit system in Australia, although clearly the evolution of resistance in the rabbit population also played a part. A simple mathematical model to demonstrate how easily group selection can (in theory) stabilize a parasite-host system is presented. This model is not meant to be a literal translation of the myxomatosis-rabbit interaction and in fact intentionally disregards hosts evolution; its purpose is to isolate the role of group selection in the parasite population.