Mouthparts of the Ponto-Caspian Invader Dikerogammarus Villosus (Amphipoda: Pontogammaridae)

Abstract

Abstract The pontogammarid amphipod Dikerogammarus villosus, originally a Ponto-Caspian faunal element, has, in the recent 15-20 years, successfully invaded various aquatic systems in Europe including Lake Constance. In these rivers and lakes it had and still has severe ecological impact on native macro-invertebrates, often eliminating the native and earlier established gammaridean species. In order to test the hypothesis that the mode of food acquisition of D. villosus is of significance for this phenomenon, we focused on the mouthparts of D. villosus, i.e., mandibles, the two pairs of maxillae and the maxillipeds using SEM. Contrary to expectations, provoked by field and laboratory observations, the results of this study show that the mouthparts of D. villosus are not highly specialized just for carnivory and predation. Indeed, the stout mandibles, with their well-developed incisors enable to kill even prey with robust integument, but other modes of feeding are possible. On the maxillulae, maxillae, and...