Comparative venomics suggests an evolutionary adaption of spider venom from predation to defense

Our data suggest that the mostly defensive utilization of venom by Cheiracanthium punctorium has resulted in unique selection pressure that gave rise to specialized venom chemistry mostly based on a single neurotoxin family and a few enzymes, including PLA2. A large fraction of the venom therefore appears to target cell membranes instead of ion channels and receptors, which are the primary targets of other spider venoms. To test this hypotheses, we carried out a comparative venomics experiment across the two main radiations of araneomorph spiders: the Araneoidea (orb-weavers and their kin) and the RTA clade (wandering spiders). We compared the araneoids Larinoides sclopetarius (Araneidae) and Meta menardi (Tetragnathidae) with C. punctorium and a closely related member of the RTA clade, Thanatus vulgaris (Philodromidae).