The formal description and classification of species biodiversity, a basic tool for applied biological research and conservation, is still very much incomplete in several taxa of aquatic invertebrates, and taxonomic knowledge of tropical faunas lags significantly behind that of faunas in north-temperate regions. The research group Limnology has a long-standing tradition of excellence in the taxonomic study of a wide range of aquatic invertebrates, with current staff focusing mostly on Copepoda (copepods), Cladocera (water fleas) and Ostracoda (seed shrimp) among the microcrustaceans, and Odonata (dragonflies and damselflies) and Chironomidae (non-biting midges) among the aquatic insects. Basic taxonomical research is subsequently combined with ecological and biogeographical research, in order to provide a better insight of the diversity and evolutionary relationships within each group. Biodiversity research on aquatic invertebrate communities and their role in the freshwater ecosystem, is crucial for conservation of these habitats throughout the world. Current projects of the research group are mainly distributed in tropical Africa, Southeast Asia, South America, and the island of Socotra (Yemen