Effects of Food Limitation and Sexual Cannibalism on Reproductive Output of the Nursery Web Spider Dolomedes triton (Araneae: Pisauridae)

Abstract

Reproductive output of free-ranging females of Dolomedes triton was not constrained by natural food limits in relation to that of sated spiders held in field cages. A two-year study revealed both seasonal and annual variation in egg number and egg-sac development time that was driven by factors other than food availability. There was a strong, positive correlation between egg numbers in first and second egg-sacs; some females produced three egg sacs under field conditions. In an experiment using field cages, reproductive output was affected by food availability to adults, female body size measured as carapace width, and by interaction between these two variables. Under both ambient field conditions and experimentally maintained satiation, fecundity increased linearly with carapace width. However, larger females failed to achieve their full, reproductive potential when food was scarce, although reproductive output of smaller females was unaffected. Females of D. triton allowed to feed on their mates did not show increased reproductive output or rate and thus do not receive any special nutrient supplements through sexual cannibalism.