DNA barcoding of British mosquitoes (Diptera, Culicidae) to support species identification, discovery of cryptic genetic diversity and monitoring invasive species

Abstract

Correct mosquito species identification is essential for mosquito and disease control programs. However, this is complicated by the difficulties in morphologically identifying some mosquito species. In this study, variation of a partial sequence of the cytochromecoxidase unit I (COI) gene was used for the molecular identification of British mosquito species and to facilitate the discovery of cryptic diversity, and monitoring invasive species. Three DNA extraction methods were compared to obtain DNA barcodes from adult specimens. In total, we analyzed 42 species belonging to the generaAedesMeigen, 1818 (21 species),AnophelesMeigen, 1818 (7 species),CoquillettidiaTheobald, 1904 (1 species),CulexLinnaeus, 1758 (6 species),CulisetaFelt, 1904 (7 species), andOrthopodomyiaTheobald, 1904 (1 species). Intraspecific genetic divergence ranged from 0% to 5.4%, while higher interspecific divergences were identified betweenAedesgeminusPeus, 1971/Culisetalitorea(Shute, 1928) (24.6%) andAe.geminus/An.plumbeusStephens, 1828 (22.5%). Taxonomic discrepancy was shown betweenAn.daciaeLinton, Nicolescu & Harbach, 2004 andAn.messeaeFalleroni, 1828 indicating the poor resolution of theCOIDNA barcoding region in separating these taxa. Other species such asAe.cantans(Meigen, 1818)/Ae.annulipes(Meigen, 1830) showed similar discrepancies indicating some limitation of this genetic marker to identify certain mosquito species. The combination of morphology and DNA barcoding is an effective approach for the identification of British mosquitoes, for invasive mosquitoes posing a threat to the UK, and for the detection of hidden diversity within species groups.