Extent and early impacts of France’s first established population of the little fire ant, Wasmannia auropunctata

Abstract The little fire ant, Wasmannia auropunctata, is one of the most widely distributed invasive alien ant species on earth, with major environmental, economic and sanitary impacts. Here we report the first established outdoor population of W. auropunctata in South East of France. We describe its detection, its extent and its early ecological impacts. Currently, the invaded area extends over around 1ha. Given the area invaded and the first reports of stings in 2019, it is likely that W. auropunctata was introduced at least five years ago. Although the introduction is probably recent, negative impacts on the abundance and richness of native ants can already be observed. We have not yet recorded any impact on other arthropods. In parallel with identifying the pathway of introduction, an eradication plan is being prepared to tackle this major environmental and economic problem. Widespread species such as the little fire ant represent a new challenge for biosecurity monitoring for Europe.