Perception of olfactory aposematic signals by jumping spiders.

Studies of aposematism are mostly focused on visual aspects of warning signalization and based on experiments with avian predators. This study presents results of experiments with an arthropod predator, a jumping spider Evarcha arcuata (Araneae: Salticidae) and olfactory (i.e., noncontact chemical) aposematic signals. Spiders were presented with chemically protected firebug Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae). After acquiring the negative experience with the bugs, the spiders were offered a choice between the firebug olfactory signal and a scentless control. Spiders actively avoided the firebug signal, showing that they are able to recognize an unprofitable prey by means of olfactory chemoreception. The results show that olfactory signals alone may function as effective means of aposematic signalization to spiders.