PARENT SESSION
Poster Session #69: Animal Ecology.
Friday, August 9. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Effects of habitat complexity and prey on cannibalism rates in a wolf spider.

TAYLOR, LISA^*,1, WISE, DAVID¹, ¹ University of Kentucky, Lexington, KY

ABSTRACT- Habitat complexity varies from one area of the forest floor to another, possibly affecting rates of cannibalism between Schizocosa wolf spiders. A previous laboratory study (Wagner and Wise 1996, Ecology) with Schizocosa spiderlings revealed that when prey were present, cannibalism rates were higher in complex than simple habitats, and when prey were absent, increasing habitat complexity had no effect on cannibalism rates. These results were unexpected, since habitat complexity generally reduces rates of cannibalism in other systems. The present laboratory study aimed to determine if this unexpected pattern also characterizes cannibalism rates between older juvenile Schizocosa. We used a 2x2 factorial design to observe the effects of habitat complexity and the presence of prey on cannibalism rates. Pairs of spiders were housed in clear plastic boxes (10 x 10 x 12cm) with a plaster-of-Paris base. "Complex" habitats contained a layer of leaf litter, while "simple" habitats had no leaf litter. "Prey" treatments consisted of a constant supply of pinhead crickets. When prey were present, habitat complexity had no effect on cannibalism rates, but when prey were absent, habitat complexity decreased cannibalism rates. These results suggest that habitat complexity and the presence of prey may have different effects on cannibalism rates in older juvenile spiders than they do on cannibalism rates in the younger spiderling stages.

KEY WORDS: cannibalism, spiders, habitat complexity