The Mosel Valley is known for its unique vineyards and warm site conditions. The region also provides a habitat for rarely seen species, including the mountain Apollo, a highly endangered and endemic butterfly subspecies that has been rapidly declining the last years. The Ecotoxicology and Community Ecology team from the RPTU Landau joined with colleagues from the Georg Petschenka’s Applied Entolomology group of the University of Hohenheim collaborate to study the exposure and impact of pesticides on the Mosel butterfly. Sampling sites were taken to determine the pesticide background contamination before the first application via helicopter starts in May.