Autecology of Limnomysis henedeni Czerniavsky, 1882 (Crustacea: Mysida) in Lake Constance, Southwestern Germany

The Ponto-Caspian mysid Limnomysis benedeni was first recorded in Lake Constance in summer 2006, and a stable population developed at the site of discovery. Although this mysid is common in the Rhine and Danube rivers, little is known about its ecology and impact in systems of invasion. We investigated the autecology of L. benedeni in habitatchpice and food experiments. In the habitat-choice experiments, highly structured habitats, i.e. , stones covered with zel· ra mussels (Dreissena polymorpha), macrophytes, and especially stonewort, were strongly preferred. In food ex eriments, L. benedeni fed mostly on food sources with a small particle size, e.g., biofilm on leaf litter, biodeposited m' terial of zebra mussels, epilithon, and phytoplankton. We also compared the L. benedeni population data from Lake C nstance with that from rivers. In Lake Constance, female L. benedeni were nearly 30% larger and carried more than th~ee times more eggs in spring (9.4±0.6mm and 28.4±5.7 eggs) than in summer (6.7±0.8mm and 8.7±2.9 eggs). The mysids present in spring might be the generation that over-wintered; in summer, this generation was probably replaced by a new generation of smaller individuals. The large brood size and the detritivorous feeding strategy might allow L. benedeni to colonize Lake Constance rapidly.