Growth of a jumping spider on nitrogen enriched prey

Abstract

The jumping spider, Phidippus audax (Hentz), preys on other spiders both intra- (cannibalism) and inter-specifically (intraguild predation). Smaller individuals become the victims in these predations. One hypothesis for the evolution of IGP/cannibalism is that consuming other carnivores (e.g., spiders) decreases a dietary stoichiometric imbalance because carnivorous prey have higher nitrogen contents than herbivorous prey. This study examined whether the nitrogen content of prey affects growth patterns of spiders by using fruit flies whose nitrogen contents were artificially enhanced. Spiders that were raised on the nitrogen rich prey grew faster than those raised on unmanipulated prey, by shortening moulting intervals. This result is consistent with the stoichiometric argument and would also have important consequences to the community dynamics of these organisms, by altering the size structure of communities with IGP and cannibalism.