Insects are extremely successful and play a pivotal role in maintaining the health of ecosystems. Yet, several insect species are in decline and are heavily impacted by environmental changes. It is all the more important that we get a deeper knowledge of the amazingly complex world of insects and their evolution, e.g. in terms of their systematic relationships, development, biodiversity and (a)biotic interactions. We apply comparative genomic / transcriptomic approaches to understand on a molecular level insect biodiversity changes, caused by evolution and / or anthropogenic environmental changes.