New evidence of an ongoing invasion: first report of Aedes japonicus in Central Italy

The rapid spread of Aedes invasive mosquitoes (AIMs) across Europe over recent decades, together with their recent expansion in northern Italy, has raised concerns about a possible southward extension of their distribution. This study investigated the presence of Aedes japonicus and Aedes koreicus , two major AIMs, in northern Tuscany, focusing on areas located along the main transport corridors connecting regions, where these species have already been reported. A 2-day entomological survey was conducted in April 2026 in the province of Massa-Carrara, northern Tuscany, to assess the presence of AIMs in Central Italy. Small villages along roads connecting the region with adjacent invaded areas were inspected, looking for adult mosquitoes, larvae, and pupae. Morphological identification of 90 adults and 35 larvae, together with molecular analyses performed on eggs, larvae, pupae, and one adult, confirmed the presence of Aedes japonicus japonicus in five municipalities of northern Tuscany. Immature stages of Ae. j. japonicus co-occurred with Aedes albopictus , Culex pipiens , Culex hortensis , and Culiseta annulata . This study provides the first evidence of Ae. japonicus in Central Italy, supporting its ongoing expansion. Its detection in several artificial breeding sites, including buckets, tyres, and a fountain basin, confirms its ecological plasticity and potential for further spread. Given its possible vector role and nuisance impact, its establishment may have public health implications. These findings highlight the need for active surveillance targeting Aedes invasive mosquitoes. Despite the short survey duration, the detection of Ae. japonicus across multiple sites suggests that the species is already firmly established in northern Tuscany.