The diagnostic utility of sequence-based assays for the molecular delimitation of the epidemiologically relevantCulex pipiens pipienstaxa (Diptera: Culicidae)

Abstract

The northern house mosquito (Culex pipiens pipiens L.) is a vector of several important pathogens and comprises two epidemiologically distinct ecotypes (molestus Forskål and pipiens). The delimitation of its ecotypes is a crucial, yet controversial step in vector surveillance due to varying diagnostic values of different characters. Therefore, we reviewed the success of a diagnostic assay based on the mitochondrial cytochrome c oxidase subunit I locus (COI) by analyzing previously published sequences of molestus and pipiens sampled in different geographical areas. Next, by genotyping individuals from Northern Serbia at this locus, we additionally assessed whether genetic structure of urban and rural Cx. p. pipiens ecotypes corresponded to the admixture pattern. Finally, to account for the different susceptibility of genetic markers to introgression, we also analyzed genetic structuring based on the ribosomal internal transcribed spacer 2 (ITS2). No latitude-dependent differentiation of Cx. p. pipiens ecotypes was found at a global level, with the COI assay further failing to accurately identify molestus and pipiens ecotypes. Likewise, both individual- (BAPS) and population-based (analysis of molecular variance and FST estimates) methods showed no significant urban/rural genetic differentiation in Serbia, indicating unhindered gene flow between different Cx. p. pipiens habitat types. The findings challenge the previous instances of Cx. p. pipiens ecotype identification, while also spotlighting the vectorial capacity of their hybrid offspring.

Comparative Phylogeography and Integrative Taxonomy of Ochlerotatus caspius (Dipera: Culicidae) and Ochlerotatus dorsalis

“…Hence, nonsignificant differences among populations, a lack of isolation by distance and the absence of associations between genetic diversity and geographic pattern were observed. Unlike the low intraspecific ITS2 rDNA variation observed herewith, the opposite pattern of variation has been documented in several other mosquito taxa [Anopheles barbirostris group van der Wulp, 1884 (Paredes-Esquivel et al 2014); Culex pipiens L, 1758 (Francuski et al 2019); Aedes albopictus (Skuse, 1894) (Gojkovic et al 2019)], thus being useful for studies of population structure and diversity (Batovska et al 2017). Thus, caution is warranted in the case of the use of ITS2 rDNA in phylogeographic study, where an evolutionary uniqueness of the species, as well as concerted evolution (Dover 1982, Otsuka 2011) should be accounted for.…”

No association between habitat, autogeny and genetics in Moroccan Culex pipiens populations

“…It should be noted that, as a single locus, CQ11 is not absolutely reliable for individual genotyping; however, it does provide rapid and economical diagnosis of mosquitoes at the population level [27]. Other single-locus methods have been proposed that have proved to be less consistent (see [46]), and while microsatellite markers appear to be more reliable, they are significantly more technical and expensive (e.g. [14]).…”