Non-target fauna reported through VespApp: a citizen science app to control the yellow-legged hornet (Vespa velutina) in Spain

The citizen science platform VespApp was launched in May 2016 (the year after the initial detection of the yellow-legged hornet Vespa velutina in the Balearic Islands, Spain) to support monitoring during the early stages of the invasion. VespApp integrated multiple communication channels from the beginning, combining both a website (vespapp.uib.es/) and a free Android application.VespApp remained active for over eight years (from May 23th, 2016, to December 9th, 2024), and users submitted photographs of both suspicious individual insects and nests, which were subsequently validated or discarded by taxonomic experts to ensure data reliability.

Insects were identified based on morphological features, and nest validation was confirmed by the presence of individuals in the images; when the nest was isolated, additional images were requested from the user to ensure taxonomic identification. To ensure nomenclatural accuracy, we standardized the taxonomy using the Global Biodiversity Information Facility (GBIF) as the primary reference database to verify accepted names, ensuring that all records aligned with current international taxonomic standards.