Prey species rarely seek-out and dismantle traps constructed by their predators. In the current study, we report an instance of targeted trap destruction by an invertebrate, and a novel context for rescue behavior. We found that foragers of the granivorous desert ant, Veromessor pergandei, identify and cooperatively dismantle spider webs (Araneae: Theridiidae, Steatoda spp. and Asagena sp.) During group foraging, workers ensnared in webs are recovered by sisters, who transport them to the nest and groom away their silk bindings. The presence of an ensnared nestmate and chemical alarm signal significantly increased the probability of web removal and nestmate retrieval. A subset of larger-bodied foragers participated in web removal, and 6.3% became tangled or were captured by spiders. Most animals that perform rescue behavior live in small groups, but V. pergandei colonies include tens of thousands of short-lived workers. To maintain their size, large colonies must collect enough seeds to produce 650 new ants each day. We hypothesize that the removal of spider webs allows for an unimpeded income of seeds on a single foraging path, during a brief daily temperature window. Despite the cost to individuals, webs are only recognized and removed when workers are captured in them.
|Date made available||2019|