Aquatic Insects is an international journal publishing original research on the systematics, biology, and ecology of aquatic and semi-aquatic insects.The subject of the research is aquatic and semi-aquatic insects, comprising taxa of four primary orders, the Ephemeroptera, Odonata, Plecoptera, and Trichoptera but also aquatic and semi-aquatic families of Hemiptera, Coleoptera, and Diptera, as well as specific representatives of Hymenoptera , Lepidoptera, Mecoptera, Megaloptera , and Neuroptera that occur in lotic and lentic habitats during part of their life cycle. Studies on other aquatic Hexapoda (i.e., Collembola) will be only accepted if space permits. Papers on other aquatic Arthropoda (e.g., Crustacea) will not be considered, except for those closely related to aquatic and semi-aquatic insects (e.g., water mites as insect parasites).The topic of the research may include a wide range of biological fields. Taxonomic revisions and descriptions of individual species will be accepted especially if additional information is included on habitat preferences, species co-existing, behavior, phenology, collecting methods, etc., that are of general interest to an international readership. Descriptions based on single specimens are discouraged. Detailed studies on morphology, physiology, behavior, and phenology of aquatic insects in all stadia of their life cycle are welcome as well as the papers with molecular and phylogenetic analyses, especially if they discuss evolutionary processes of the biological, ecological, and faunistic formation of the group.