Biogeographia – The Journal of Integrative Biogeography

The red imported fire ant, Solenopsis invicta Buren, 1972, one of the most impactful invasive species worldwide, was first reported in Europe in 2023. Residents’ reports led to the discovery of a 23 km long invasion along the southeastern coast of Sicily (Italy). In 2024, local authorities started an eradication programme using hot water and poisonous baits, while the European Commission opened an infringement procedure against Italy for failing to prevent and manage the invasion in a timely manner. Here, we report additional occurrence sites, including from three new provinces about 60 km westward and 120 km north, increasing the area of occupancy from 36 km² to 88 km² and the extent of occurrence from 53 km² to 6,200 km². The species is detected for the first time in woodland sites far from urban and coastal areas. We also gathered 151 literature and 1,858 unpublished occurrence records of other ants in an area of 3,576 km² surrounding the S. invicta sites. Seventy-eight other ant species occur near the invaded sites, including 68 native, 6 non-native, and 4 of unknown status. Among the native species detected, 11 are island endemic and subendemic, and three are listed as Vulnerable by the global IUCN Red List. Several non-native ants occurred in coastal areas invaded by S. invicta. An updated checklist of the ant fauna of Sicily, counting 136 species, is provided as a tool for researchers and policymakers. This ecological knowledge is important for informing evidence-based conservation policies that aim to mitigate invasive species’ impacts while safeguarding native ecosystems.