Vision-based innate aversion to ants and ant mimics

Innate vision-based aversions to model and mimic were investigatedusing a mimicry system in which the models were ants (Formicidae),and both the mimics and the predators were jumping spiders (Salticidae).Jumping spiders are a large group of predatory invertebratesthat usually prey opportunistically on prey of similar size.We used 12 representative species from this group, the "ordinarysalticids" as predators. The mimics considered belonged to anothergroup, salticids that resemble ants. A choice arena containingan empty chamber and a stimulus chamber was used for testingpredator responses to a variety of dead arthropods (ants, antmimics, and an array of non–ant-like species) mountedin a lifelike posture. When presented with visual cues fromarthropods other than ants or ant-like salticids, naive predatorschose the empty chamber no more often than the stimulus chamber.However, when visual cues were from ants or from ant-like salticids,ordinary salticids chose the empty chamber significantly moreoften than the stimulus chamber. These findings suggest learningby the predator is not necessary in order for ant-like salticidsto gain Batesian mimicry advantages.