Chironomid Larval Size and Case Presence Influence Capture Success Achieved by Dragonfly Larvae

Abstract

Odonate larvae have been characterized as nonselective predators because they are able to feed on a wide range of prey species. However, the relative proportions of particular prey species in the diet do not always match the relative abundances of those prey in the environment. This study examined the effects of two factors that potentially influence the diet of dragonfly larvae: prey size and presence of protective prey covering. Late-instar Leucorrhinia intacta larvae captured significantly greater numbers of large (10 mm) chironomid larvae over small (5 mm) chironomid larvae. Large chironomid larvae removed from their gelatinous cases were taken in significantly greater numbers than comparable larvae with cases. These results are considered relative to the potential impact of odonate larvae on prey populations found in the littoral zone.