Egg cannibalism by passion vine specialist Disonycha Chevrolat beetles (Coleoptera: Chrysomelidae: Galerucinae: Alticini)

Abstract

Cannibalistic behavior is now recognized to be an important component of nutritional ecology in both carnivorous and herbivorous species, including many beetle families (Englert and Thomas 1970; Beaver 1974; Dickinson 1992; Bartlett 1987; Alabi et al. 2008). This habit was historically viewed by an incidental outcome of unnaturally crowded laboratory situations with little ecological importance (Fox 1975), but it is increasingly acknowledged that cannibalism represents a potentially advantageous behavior (Richardson et al. 2010). Here we report on multiple cases of egg cannibalism, or conspecific oophagy, by adults of two species of passion vine (Passiflora Linnaeus: Passifloraceae) specialist flea beetles in the genus Disonycha Chevrolat (Coleoptera: Chrysomelidae: Galerucinae: Alticini). This is the first report of egg cannibalism from the Galerucinae, and to our knowledge, only the fourth report of egg cannibalism by adults in the Chrysomelidae; the other three reports are of adult Chrysomelinae species eating conspecific eggs (Dickinson 1992; McCauley 1992; Schrod et al. 1996). We conclude this note with several questions raised by our observations, followed by a discussion that may contribute to explanations of this behavior.