Female receptivity and male mate-guarding in the jewel spider Gasteracantha minax Thorell (Araneidae)

Abstract

In field populations, several male jewel spiders Gasteracantha minax Thorell (Araneidae) may be found at the periphery of the orb web of a female, indicating that males may compete for fertilisation success. Laboratory experiments revealed that virgin female G. minax readily remate shortly after their first mating. However, they appear to enter a refractory period between 1 and 24 h postmating and respond aggressively to courting males. Males that have mated with a female initially defend her from rival males but cease to do so after the onset of the refractory period. These data can be interpreted within the context of mate guarding and sperm competition. There is marked size dimorphism in this species, which may be the result of selection for protandry. In contrast with other orb-weaving spiders, this selection pressure does not seem to be counterbalanced by selection for larger male size through either sexual cannibalism or male-male competition.