Intersexual conflict in spiders

Reproductive strategies of males and females usually differ and, as a conse quence, may impose asymmetric costs of reproduction on the two sexes and re sult in conflict between the sexes. In spiders, males do not provide parent al care and females can store sufficient sperm for several clutches. These characteristics define the stage for a conflict between males and females t hat occurs mainly over the frequency of mating. Factors such as sexual size dimorphism, operational sex ratio, mating system and life-history strategi cs are likely to influence the degree of conflict and its outcome for diffe rent species. Male spiders may suffer large costs of mating due to mate sea rch, assessment of female condition, courtship and cannibalistic tendencies of their mates. Courtship may reduce cannibalism, although in some cases, males benefit from being cannibalised by having an increased fertilisation rate or greater offspring fitness. In some species, limited mating capaciti es will increase the value of the current mating relative to future reprodu ction. Apart from a possible benefit of genetic variability within a clutch , females may not benefit from multiple mating and multiple mating may even be costly. Exceptions occur if additional resources are provided by males or when offspring fitness increases with additional mating. Forced copulati on, prey theft, loss of the web and reduction of foraging time can all resu lt in reduced reproductive success for females. We discuss the interacting influences of life-history traits (especially patterns of growth and matura tion and sexual size dimorphism) and the reproductive strategies of males a nd females, using a semelparous spider, Stegodyphus lineatus (Eresidae), as an example of a species in which males and females can have strongly confl icting interests.