Data from: Destruction of spider webs and rescue of ensnared nestmates by a granivorous desert ant (Veromessor pergandei)



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.,Data for Table A1, silk removal in a natural contextThese data show the presence or absence of factors associated with 29 spider webs found on Veromessor pergandei foraging columns and nest mounds. For each variable, 0 = no, 1 = yes. The statistical analysis of this data set is presented in Table A1.Silk removal observations, Data for Table A1.csvData for Table A2, Silk-gland-dummy assayData represent the number of workers responding to 5 different stimuli, across 16 field colonies. The statistical analysis of this data set is presented in Table A2.Silk-gland-dummy assay, Data for Table A2.csvData for Wilcoxon ranked sign test, head vs gaster gland assay,Data represent worker responses to each of 3 stimuli, presented to 30 unique colonies. Paired responses to head and gaster contents were compared with a Wilcoxon ranked sign test for 28/30 unique pairs.Head vs gaster gland assay, Wilcoxon ranked sign test.csv,
Date made availableJan 1 2019

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