Predatory behaviour and predatory versatility in young larvae of the dragonflyXanthocnemis zealandica(Odonata, Coenagrionidae)

Abstract

Abstract The predatory activities of naive second‐instar Xanthocnemis zealandica larvae (the first free‐living stage) were investigated under six treatments—no prey, ciliates, rotifers, nematodes (two densities), copepods, and cladocerans. Some differences observed could have been due to sensory, or to morphological, limitations of the predator. Other behaviour patterns strongly indicated some CNS‐mediated response. Larvae apparently distinguished between prey types and used prey‐specific conditional behaviours (i.e. displayed predatory versatility). Changes in response were observed during exposure to unpalatable prey but did not occur when larvae ate palatable prey or repeatedly made futile attacks on invulnerable prey. Such changes indicate learning. In contrast to calopterygid species investigated by earlier authors, X. zealandica second‐instar larvae were both more co‐ordinated and more flexible in their predatory behaviour. The predatory behaviour of small insect larvae may be more complex than has traditionally been assumed.