Evidence that web reduction by western black widow males functions in sexual communication

Abstract

Abstract A well-accepted function of courtship in sexually dimorphic and cannibalistic spiders is suppression of female predatory responses. We quantitatively analysed courtship in the western black widow, Latrodectus hesperus Chamberlin and Ivie (Araneae: Theridiidae), to determine the behavioural elements of the males’ courtship that are correlated with mating success and/or the females’ responses. The 58% of males that engaged in web reduction elicited fewer aggressive responses from females and induced female quiescence more quickly than did males not exhibiting web reduction behaviour. Our data suggest that web reduction by male L. hesperus functions in sexual communication, a context not previously explored.