Attack strategies of a spider kleptoparasite: effects of prey availability and host colony size

Abstract

Argyrodes ululans, a kleptoparasitic spider that specializes in stealing prey from the social spider, Anelosimus eximius, faces a variety of foraging situations depending upon the number of host spiders involved in prey capture and defence, and prey availability. The ability of A. ululans to modify its mode of attack may therefore be essential to ensure its success in obtaining food. Kleptoparasite hunger level, host colony size and prey size were manipulated and detailed observations of behaviour were made to determine whether A. ululans modifies its stealing strategy in response to these changing conditions. Argyrodes ululans initiated an attack based on its hunger state and the size of the prey tackled, and altered the relative frequencies of its component stealing behaviour patterns according to the number of host spiders that responded to capture the prey. These adjustments in stealing tactics allow A. ululans to maximize its success in acquiring prey and to conserve energy used for foraging.