Choice of Prey Body Parts for Effective Feeding by Predaceous Diving Beetle Larvae, Dytiscus sharpi sharpi (Wehncke) (Coleoptera: Dytiscidae)

Abstract

Diving beetle larvae use their mandibles in two ways: capturing prey and sucking their body fluid. Catching and consuming the prey's most nutritious body part leads to the highest feeding efficiency. To test this, Dytiscus sharpi sharpi larvae were given tadpoles (Rana ornativentris) as food and their feeding behaviors were observed. Dytiscus larvae preferred to catch tadpoles by the abdomens rather than by other parts. Tadpoles soon became immobilized and in most cases the beetle larvae started eating abdomens first. Beetle larvae tried to change biting site to tadpole's abdomen when the tadpole was initially caught by the head or tail. More food was absorbed from the abdomen than the head or tail suggesting that the feeding behavior of beetle larva is optimized to obtain nutrition efficiently from the tadpole abdomen.