Evolutionary physiology of the cost of reproduction

The concept of a cost of reproduction has associations with a variety of other ideas in population biology, among them trade-offs and antagonistic pleiotropy. Within the concept of a cost of reproduction, a variety of components can be distinguished, such as physiological and ecological costs of reproduction. This article concentrates on the former type of cost. Empirically, a variety of approaches can be, and have been, used to analyze the cost of reproduction. Three are distinguished: genetic, environmental, and physiological. These are discussed first in general terms and second with specific reference to research on laboratory evolution in Drosophila. The latter discussion serves to focus and to instantiate the general analysis of the field. Emerging themes from this area of research include the environmental plasticity of costs of reproduction, the difficulties facing simple trade-off theories, and the critical role of physiological integration in determining costs at the organismal level.