NO ASSOCIATION BETWEEN SEXUAL SIZE DIMORPHISM AND LIFE-HISTORIES IN SPIDERS

In spiders, females are commonly larger than males. The majority of hy potheses that attempt to explain sexual size dimorphism in spiders con centrate on reduction in male size, although there is evidence to sugg est that the independent evolution of marked sexual size dimorphism an d reversion to a less extreme dimorphic state has occurred several tim es. Recent debate has centred on two conflicting hypotheses involving male dwarfism and increased female size through fecundity selection, a nd has focused on the golden orb-weaving spider, Nephila clavipes (Tet ragnathidae), and its relatives. In Nephila, males are tiny in compari son to females, however, other orb-web spiders do not show such extrem es in dimorphism. Here, we incorporate phylogeny into a comparative in vestigation of the patterns of sexual dimorphism predicted by the hypo thesis of male dwarfism via sex-linked differential mortality during m ate searching and note an absence of supporting evidence. There was no evidence of the predicted association between male and female size an d sexual size dimorphism with life histories, exemplified by variation in predatory strategies, in spiders.