Exploring the utility of phylogenetic analysis of cytochrome oxidase gene subunit I as a complementary tool to classical taxonomical identification of phlebotomine sand fly species (Diptera, Psychodidae) from southern Europe

Phlebotomine sand flies (Diptera, Psychodidae) are known to be vectors of several pathogens such as Leishmania and Phlebovirus genera. The identification of phlebotomine sand fly species is currently based on morphological characters, and requires considerable taxonomic expertise and skilfulness, but may be complemented by DNA-based analyses for (i) accurate species identification and (ii) for estimating sand fly diversity. The aim of this study was to evaluate the utility of mitochondrial cytochrome oxidase gene subunit I (cox1) sequence analysis as a complementary tool to classical taxonomical for the identification of the most prevalent phlebotomine sand fly species from southern Europe (i.e. Phlebotomus ariasi, P. perniciosus, P. sergenti and Sergentomyia minuta).Phylogenetic analyses of cox1 sequences allowed conclusive assignment of most of the sand flies into individual species, and revealed the genetic heterogeneity that characterizes some of the identified genetic clusters. Nevertheless, it showed some limitations, as it failed to (i) allocate correctly all of all species of a given subgenus to a single lineage, or (ii) conclusively identify sequences amplified from individuals classified morphologically as P. ariasi. A more extensive analysis of cox1 sequences together with morphometric characterization of specimens from different geographic areas/regions might be useful for the correct assessment of the phylogenetic relationship within the P. ariasi/P. chadlii cluster and/or help to ascertain the usefulness of cox1 for molecular taxonomy of sand flies.