Factors affecting cannibalism among newly hatched wolf spiders (Lycosidae, Pardosa amentata)

Cannibalism is a common phenomenon among young wolf spiders (Lycosidae). The put-pose of this study was to investigate how various factors influence cannibalistic tendencies in hatchlings of Pordosa amentota (Clerk 1757). The basic experimental approach was to place pairs of unfed hatchlings of similar body mass in small containers without prey and to measure if and when cannibalism happened. From the data, we identified three different cannibalistic strategies. One large group of hatchlings never cannibalized and thus died from starvation. Another group cannibalized shortly before the time at which they were predicted to die from starvation. In these spiders, there was it strong positive relationship between average body mass of the contestants and their latency to cannibalize. A (third group) cannibalized quickly and the latency to cannibalize in these spiders was independent of body mass. We also tested if cannibalistic tendencies were higher among unrelated pairs than among pairs of siblings, but we did not find any support for this hypothesis. In another experiment we tested if maternal effects influenced cannibalism, i.e. if siblings from certain mothers were more cannibalistic than siblings from others. We did not find any evidence that maternal effects influenced whether or not cannibalism occurred. However, when cannibalism did occur, the latency to cannibalize varied significantly among siblings from different mothers beyond what would have been predicted solely from hatchling body mass.