WILDER, S. M.*; RYPSTRA, A. L.; Miami University, Oxford, OH; Miami University, Hamilton, OH: A Comparison of Precopulatory and Postcopulatory Sexual Cannibalism in a Wolf Spider (Araneae, Lycosidae)

In many species that exhibit sexual cannibalism, the killing and consumption of the male by the female can occur either before or after mating. Precopulatory cannibalism may have a higher likelihood of success relative to postcopulatory cannibalism because before mating males are approaching and courting females, whereas after mating males are moving away from females. The purpose of this study was to test if precopulatory sexual cannibalism occurs more quickly and requires fewer female attacks than postcopulatory sexual cannibalism in the wolf spider Hogna helluo. We tested this by randomly pairing males and females in arenas in the laboratory. Using data from all trials in which sexual cannibalism occurred, postcopulatory sexual cannibalism occurred more quickly, required fewer lunges by females and tended to require fewer interactions between males and females. But in some trials, the latency to sexual cannibalism was unrealistically long. Hence, to create a more realistic data set, we restricted the data set to occurrences of sexual cannibalism that were less than 180 s from either a) the start of the trial, for trials with precopulatory cannibalism, or b) when the male dismounted, for trials with postcopulatory cannibalism. The more realistic data set revealed the opposite results: precopulatory sexual cannibalism occurred more quickly, required fewer interactions between male and female and tended to require fewer chases by the female than postcopulatory sexual cannibalism. These results suggest that food-limited, virgin females must decide between not mating and having a better chance of cannibalizing a male or mating and having a poorer chance of cannibalizing a male. These results also underscore the need to use biologically realistic data when evaluating hypotheses in the laboratory.