ANIMAL MATING SYSTEMS - A SYNTHESIS BASED ON SELECTION THEORY

Following principles used by A. J. Bateman, we identify the relationsh ip between fecundity and mating success as the central feature in the operation of mating systems. Using selection theory from the field of quantitative genetics, we define the sexual selection gradient as the average slope of the relationship between fecundity and mating success and show how it can be estimated from data. We argue that sexual sele ction gradients are the key to understanding how the intensity of sexu al selection is affected by mate provisioning, parental investment, an d sex ratio.