Vision-based innate aversion to ants and ant mimics

Abstract

Innate vision-based aversions to model and mimic were investigated using 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 invertebrates that usually prey opportunistically on prey of similar size. We used 12 representative species from this group, the ‘‘ordinary salticids’’ as predators. The mimics considered belonged to another group, salticids that resemble ants. A choice arena containing an empty chamber and a stimulus chamber was used for testing predator responses to a variety of dead arthropods (ants, ant mimics, and an array of non–ant-like species) mounted in a lifelike posture. When presented with visual cues from arthropods other than ants or ant-like salticids, naive predators chose 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 more often than the stimulus chamber. These findings suggest learning by the predator is not necessary in order for ant-like salticids to gain Batesian mimicry advantages. Key words: ants, innate aversion, mimicry, myrmecomorphy, spiders, vision. [Behav Ecol]