<scp>DNA</scp> Barcoding for the Identification of Adult Mosquitoes (Diptera: Culicidae) in Western Australia

Precise mosquito identification is integral to effective arbovirus surveillance. Nonetheless, the conventional morphological approach to identifying mosquito species is laborious, demands expertise and presents challenges when specimens are damaged. DNA barcoding offers a promising alternative, surmounting challenges inherent in morphological identification. To integrate DNA barcoding into arbovirus surveillance effectively, a robust dataset of mosquito barcode sequences is required. This study established a comprehensive repository of Cytochrome Oxidase I (COI) barcodes, encompassing 177 samples representing 45 mosquito species from southern and northern Western Australia (WA), including 16 species which have not been previously barcoded. The average intraspecific and interspecific genetic distances were 1% and 6.8%, respectively. <i>Anopheles annulipes</i> sensu lato had the highest intraspecific distance at 9.1%, signifying a genetically diverse species. While validating the potential of COI barcodes to accurately differentiate mosquito species, we identified that some species pairs have low COI divergence. This includes <i>Aedes clelandi</i> and <i>Ae. hesperonotius</i>, <i>Tripteroides atripes</i> and <i>Tp. punctolaeralis</i> and <i>Ae. turneri</i> and <i>Ae. stricklandi</i>. In addition, we observed ambiguity in identification of the members of <i>Culex sitiens</i> subgroup (<i>Cx. annulirostris</i>, <i>Cx. palpalis</i> and <i>Cx. sitiens</i>) and three members of Cx. pipiens complex (<i>Cx. australicus</i>, <i>Cx. globocoxitus</i>, <i>Cx. quinquefasciatus</i>). In summary, despite presenting challenges in the identification of some mosquito species, the COI barcode accurately identified most of the species and generated a valuable resource that will support the WA arbovirus surveillance program and enhance public health intervention strategies for mosquito-borne disease control.