Assessing non-native invasive Orthoptera in Europe

Abstract Orthoptera encompasses 29,000 species. Due to their ability to migrate long-distances through hitchhiking or active dispersal but also due to their wide dietary spectrum, several orthoptera species can pose a phytosanitary threat. Despite information being scarce and contrasting among sources, we compiled literature on non-native Orthoptera species in Europe for this scoping review. We identified 41 relevant species, 35 are non-native (non-native to Europe n = 8, partly native to Europe n = 21, native range unknown/no information available n = 6), two arguably invasive species to Europe due to proven impacts, two are questionable and another two cryptogenic. Of these, 23 species are considered established. The two invasive orthopterans were the Moroccan Locust Dociostaurus maroccanus and the Desert Locust Schistocerca gregaria , which are invasive in several European countries. Non-native orthopterans can react very positively to climate warming, resulting in expanding geographical distributions. Furthermore, the number of invasive orthopterans in Europe is likely higher due to a paucity of assessments, increasing introduction rates, and observable impacts on agriculture as well as native species. While e.g., the Migratory Locust Locusta migratoria causes large-scale damage to crops by forming swarms, the southern oak bush cricket Meconema meridionale has a negative impact on native species, but neither species is listed as invasive. Besides this, there are other non-native Orthoptera species that could become invasive given increasing reproduction rates due to suitable conditions. Globalization and rising temperatures due to global warming are both increasing introduction rates and concomitantly the availability of suitable locations for reproduction, successful establishments, and finally swarm building. This will increase the probability of damages to agriculture, thus the economy and native biodiversity, eventually endangering human well-being. It is therefore important to monitor and study the invasiveness and impacts of non-native Orthoptera species to develop efficient management or preventive mitigation strategies.