Are brown recluse spiders, Loxosceles reclusa (Araneae, Sicariidae) scavengers? The influence of predator satiation, prey size, and prey quality

摘要

I examined prey choice of the brown recluse spider (Loxosceles reclusa Gertsch & Mulaik 1940) with reference to unusual scavenging behavior originally reported by Sandidge (2003). Because scavenging is an unexpected behavior in normally predatory spiders, I hypothesized that special circumstances must converge for the brown recluse to prefer dead prey over live prey. I offered crickets (Acheta domesticus) to brown recluses in several choice experiments. I varied predator satiation (spiders not fed for two or four weeks), prey size (small or large), and prey quality (live, fresh dead, dead 1-2 days, 1 week or 1 month). Overall, recluses preferred live prey over dead, but their choice was influenced by all three variables. Recluses were more likely toscavenge when presented with large live prey paired with dead prey of equal size than when presented with small live and dead prey. Spiders that had fed recently were more likely to scavenge. Finally, recluses preferred dead prey that were freshly killed or less than 24 hours old to items dead for longer periods. My results suggest that scavenging is an opportunistic behavior in recluses that requires specific circumstances that may rarely occur in nature.