The Effect of Population Structure on the Evolution of Mutualism: A Field Test Involving Burying Beetles and Their Phoretic Mites

Abstract

Theoretically, when the benefits of mutualism are shared among a group of neighbors, the evolution of mutualism is impeded. Little is known about the values of important parameters such as the costs and benefits of mutualism or salient aspects of population structure. A species of phoretic mite (Poecilochirus necrophori: Acari, Parasitidae) strongly enhances the breeding success of its beetle carrier, even though the benefits of this mutualism must be shared among a fairly large group. The group size argument should not be used to argue categorically against the prevalence of mutualism in nature.