Longevity and the Evolution of Polygamy

Abstract

A model emphasizing the role of longevity in the evolution of polygamy has been developed, with particular reference to the model postulated by Downhower and Armitage (1971). It is suggested that (1) animal species with long expected life spans may be able to sacrifice maximal yearly reproduction if, by doing so, they increase their probability of survival, and (2) consequently, a measure of "yearly fitness" may not be a good estimate of an individual's "total fitness" if he is very long-lived. The model emphasizes individual female fitness as being critical in explaining the evolution of polygamy rather than treating it as an outcome of different strategies of males and females.