Ballistic defaecation by anisopteran larvae (Odonata): a way to increase foraging success?

Abstract

The article considers the phenomenon of ballistic defaecation by odonate larvae, exhibited by certain Anisoptera but not by any Zygoptera, and explores two possibilities: (1) that ballistic defaecation in Anisoptera may correlate with increased foraging success (the ‘Wudkevich Hypothesis’) by distancing the prey’s alarm pheromone, persisting in the pellet after defaecation, from the larva’s ambush site; and (2) that its absence in Zygoptera may correlate with their much richer repertoire of intraspecific agonistic behaviour, perhaps reflecting the need to change, and compete for, ambush sites more often. Attention is drawn to kinds of information that could throw light on the Wudkevich Hypothesis and to the design of experiments that would sustain or refute it; and mention is made of the possible implications for larvae of Zygoptera of their ability to learn to modify their antipredation behaviour in response to chemical cues emitted by their predators or by injured conspecifics.

Keywords: Odonata, dragonfly, larvae, Anisoptera, defaecation, alarm pheromone, chemical cues

Issue section: Article