Double Deception: Ant-Mimicking Spiders Elude Both Visually- and Chemically-Oriented Predators

Biological mimicry is often multimodal, in that a mimic reinforces its resemblance to another organism via different kinds of signals that can be perceived by a specific target audience. In this paper we describe a novel scenario, in which a mimic deceives at least two distinct audiences, each of which relies primarily on a different sensory modality for decision-making. We have previously shown that Peckhamia picata, a myrmecomorphic spider that morphologically and behaviorally resembles the ant Camponotus nearcticus, experiences reduced predation by visually-oriented jumping spiders. Here we report that Peckhamia also faces reduced aggression from spider-hunting sphecid wasps as well as from its model ant, both of which use chemical cues to identify prey. We also report that Peckhamia does not chemically resemble its model ants, and that its total cuticular hydrocarbons are significantly lower than those of the ants and non-mimic spiders. Although further studies are needed to clarify the basis of Peckhamia's chemically-mediated protection, to our knowledge, such ‘double deception,’ in which a single organism sends misleading visual cues to one set of predators while chemically misleading another set, has not been reported; however, it is likely to be common among what have until now been considered purely visual mimics.