Genetic diversity and morphology of South Korean Aedes koreicus (Diptera: Culicidae) provide insights into the origin of European populations

Aedes koreicus (Edwards, 1917) is native to Korea, northern China, and the Russian Far East, and has gained attention following its first detection in Europe in 2008 and subsequent spread across Europe. The Korean Peninsula, which includes the type locality of Ae. koreicus , has been regarded as a potential source region for invasive populations of this species, along with other parts of its native range. However, little is known about the genetic and morphological attributes of Korean populations. We obtained DNA from 172 specimens of Ae. koreicus from 19 populations in South Korea, including Jeju Island. Genetic diversity and population structure were assessed using the mitochondrial COI marker, with 147 European sequences and one northern Chinese sequence available from GenBank included in the comparison. We also examined 520 specimens from 40 South Korean localities to evaluate variation in morphological characters previously reported in European studies. A total of 23 COI haplotypes were identified among 172 specimens from 19 sites in South Korea. H2 was the most frequent and widely distributed haplotype (116/172, 67.4%), occurring at 17 sites. Among the 147 European sequences, comprised 35 haplotypes, only one of which, H2, was shared between South Korean samples and German sequences. Pairwise F ST comparisons showed significant differentiation among Korean Peninsula, Jeju Island, and most European regions except Germany, while AMOVA further supported genetic structuring among these three groups. Morphological characters of South Korean populations, including those from Jeju Island, were similar to those reported from Germany and fell within the range of variation previously documented from Korean specimens. However, the characters differed from variants reported from Belgium, Italy, and other European populations. South Korean populations showed genetic and morphological differences from several European populations of Ae. koreicus . Although additional genetic data and broader sampling in both the native and invaded ranges are required for validation, our results suggest that European Ae. koreicus populations are unlikely to have originated solely from Korea, indicating the possibility of additional source regions within the native range outside Korea.