Non‐consumptive killing of a conspecific dragonfly

Abstract

Intraspecific competition for resources, such as food, mates, or territory, is widespread across the animal kingdom. Larval dragonflies (Epitheca cynosura), for example, commonly cannibalize each other (Ecology 1996; doi.org/10.2307/2265668); however, larval damselflies (Megaloprepus coerulatus) are sometimes killed but not consumed by conspecifics (Oecologia 1994; doi.org/10.1007/bf00317138), which can reduce competition for food. Adult dragonflies, as in the case of Perithemis tenera, are known to defend breeding territories near water, whereby they fight off intruding conspecifics (Ethology 2004; doi.org/10.1046/j.1439-0310.2003.00942.x). On occasion, a territorial male may even catch a competitor, in which case that competitor would likely end up as food. Here, I observed a female western pondhawk (Erythemis collocata) chase and kill, but not consume, another female conspecific that had recently emerged. The attacking E collocata chewed through the pronotum (a cover of the thorax) of the attacked E collocata, which stopped moving immediately. The aggressor then departed to the shore of the pond, with no signs of returning to its victim.