EFFECTS OF FOOD LIMITATION AND SEXUAL CANNIBALISM ON REPRODUCTIVE OUTPUT OF THE NURSERY WEB SPIDER DOLOMEDES TRITON (ARANEAE, PISAURIDAE)

Reproductive output of free-ranging females of Dolomedes triton was no t constrained by natural food limits in relation to that of sated spid ers held in field cages. A two-year study revealed both seasonal and a nnual variation in egg number and egg-sac development time that was dr iven by factors other than food availability. There was a strong, posi tive correlation between egg numbers in first and second egg-sacs; som e females produced three egg sacs under field conditions. In an experi ment using field cages, reproductive output was affected by food avail ability to adults, female body size measured as carapace width, and by interaction between these two variables. Under both ambient field con ditions and experimentally maintained satiation, fecundity increased l inearly with carapace width. However, larger females failed to achieve their full, reproductive potential when food was scarce, although rep roductive output of smaller females was unaffected. Females of D. trit on allowed to feed on their mates did not show increased reproductive output or rate and thus do not receive any special nutrient supplement s through sexual cannibalism.