Copulation and sperm release in Gasteracantha cancriformis (Araneae: Araneidae):: differential male behaviour based on female mating history

Female spiders have two separate reproductive tracts, one on each side of the body, which receive and store sperm. Thus, females may be virgin or nonvirgin on both sides, or virgin on one side and nonvirgin on the other side. To examine whether male orb-weaving spiders, G. cancriformis, respond differentially to females based on mating history, we presented mates to (1) virgin females, (2) females that had previously mated with one of their two tracts and (3) females that had mated previously with both reproductive tracts. Prior to copulation, males showed no differential responses in terms of latency to courtship, number of courtship bouts, number of insertion attempts, or latency to copulation. Female mating history influenced copulatory frequency and sperm release by the male, but not duration of copulation. Nearly all males copulated twice with virgin females, once with each reproductive tract. They released nearly all sperm contained in their palps. Males that encountered nonvirgin reproductive tracts were more likely to depart after a single copulation without attempting a second. Such males rarely released sperm, but the few that did released as many as males mating with virgin tracts. Thus, sperm were released in an all-or-none fashion. Female mating history did not influence the frequency of intersexual cannibalism. This suggests that differential response by males is more likely related to female patterns of sperm use than to high levels of intersexual killing. (C) 2001 The Association for the Study of Animal Behaviour.