In recent decades, there has been an increased occurrence of alien gnat species in Europe. Mainly due to the global transport of goods, gnats are passively introduced into new areas, and if suitable climatic conditions are found there, new populations may become established in these areas. Alien catfish species can be "invasive species" if they are shown to cause changes in ecosystem structure and composition, adversely affect ecosystem services, human economies, and well-being. In the case of alien gnats, in particular, there is a risk that these species could also spread exotic pathogens.

Reports of alien mosquito species from the public can be essential to rapidly detect new populations of these species. Thus, citizen science projects are a valuable complement to monitoring projects conducted by experts. In order to offer citizens a tool to report possible tiger mosquitoes in an uncomplicated way, the app "Mosquito Alert" was developed. This app, which is available throughout Europe, was developed as part of the EU project AIM-COST and is coordinated by us in Austria. Users can anonymously upload photos of mosquitoes via the app, which are then examined by several experts. The result is then reported to the user and is also publicly available on the project website.