First Record of the Mosquito Aedes koreicus (Diptera: Culicidae) in Croatia

Aedes koreicus, the Korean bush mosquito, has emerged as a significant invasive threat across Europe since its initial detection in Belgium in 2008. Native to East Asia, this cold-tolerant, container-breeding species has established populations in more than a dozen European countries. During entomological field sampling in the Buzet area (Istria, Croatia), two used-tire depots in the village of Štrped were encountered and identified as potentially suitable breeding habitats for container-breeding mosquitoes. Following the initial detection of these mosquitoes' larvae, the locality was revisited four times from March to May 2026. Dippers of different sizes were used to sample larvae in the tires. Of the 132 larvae collected, eight species were morphologically identified. Nineteen specimens were identified as Ae. koreicus and were detected during each visit. The identification of Ae. koreicus was confirmed by molecular analysis. Sequencing and analysis of cytochrome c oxidase I showed high similarity among Ae. koreicus populations across Europe. This finding confirms the presence of Ae. koreicus in Croatia, which could potentially lead to further establishment, and highlights the need for continued surveillance of invasive mosquito species.