Heritability of a male character chosen by females of the field cricket,Gryllus bimaculatus

Summary Body size in the field cricket,Gryllus bimaculatus, contributes to fitness through its effects on competitive male mating success and female fecundity and is a character chosen by females at mating. If females are to benefit from preferentially mating with large males they must be able to pass on the advantages of large size to their offspring. The heritabilities of four aspects of body size were estimated by parent-offspring regression. All aspects were shown to have heritable genetic variation despite the fact that theory predicts characters which contribute to fitness should not be heritable. There may therefore be the potential for female choice in this species to be adaptive. Some possible mechanisms for the maintenance of heritable variation are discussed.