An investigation into the morphological and behavioral adaptations of the aquatic larvae of Aquatica leii (Coleoptera: Lampyridae) to prey upon freshwater snails that serve as intermediate hosts for the liver fluke

The freshwater gastropods Lymnaea stagnalis and Hippeutis sp. are intermediate hosts of parasites that are harmful to humans and animals. In order to evaluate the predatory capacity of the aquatic larvae of the firefly Aquatica leii Fu and Ballantyne (2006) on these freshwater snails, we carried out observations on morphological adaptations of these larvae that enable them to attack and devour the snails and we conducted a series of laboratory-based predation experiments, whose aims were to determine daily predation rate, differential predation on small and large sized snails, selective predation on three different species of snail, and overall dietary requirements. Observations on the external morphologies of the larvae revealed well-developed pygypodia and specialized mouthparts to attack and overpower water snails. Feeding communally on freshwater snails, larvae commonly form aggregations of many individuals. Although the larvae have a wide dietary spectrum and can also feed on dead snails and other animals, food choice tests showed that larval A. leii prefer live L. stagnalis Linnaeaus, 1756 to all other foods tested, including the two other aquatic snails Bellamya purificata Heude, 1890 and Hippeutis sp. Our observations suggest that larval A. leii could be potentially suitable bio-control agents in connection with freshwater snail populations. (C) 2012 Elsevier Inc. All rights reserved.