Hybridization and population structure of the Culex pipiens complex in the islands of Macaronesia

Abstract

The Culex pipiens complex includes two widespread mosquito vector species, Cx. pipiens and Cx. quinquefasciatus. The distribution of these species varies in latitude, with the former being present in temperate regions and the latter in tropical and subtropical regions. However, their distribution range overlaps in certain areas and interspecific hybridization has been documented. Genetic introgression between these species may have epidemiological repercussions for West Nile virus (WNV) transmission. Bayesian clustering analysis based on multilocus genotypes of 12 microsatellites was used to determine levels of hybridization between these two species in Macaronesian islands, the only contact zone described in West Africa. The distribution of the two species reflects both the islands' biogeography and historical aspects of human colonization. Madeira Island displayed a homogenous population of Cx. pipiens, whereas Cape Verde showed a more intriguing scenario with extensive hybridization. In the islands of Brava and Santiago, only Cx. quinquefasciatus was found, while in Fogo and Maio high hybrid rates (~40%) between the two species were detected. Within the admixed populations, second‐generation hybrids (~50%) were identified suggesting a lack of isolation mechanisms. The observed levels of hybridization may locally potentiate the transmission to humans of zoonotic arboviruses such as WNV.

Genetic diversity of Culex pipiens mosquitoes in distinct populations from Europe: contribution of Cx. quinquefasciatus in Mediterranean populations

“…quinquefasciatus and Cx. pipiens s.s. form pipiens or form molestus , in some contact zones such as North America [ 5 – 8 ], Mexico [ 9 ], Argentina [ 10 , 11 ], the Cape Verde Islands in the Atlantic Ocean, Africa [ 12 ], and in Greece (Europe) [ 13 ], while exhibiting complete isolation in other regions such as East Africa [ 14 ]. Hybrids between other members of Culex pipiens complex, such as Cx.…”

Comparison of the Potential for Different Genetic Forms in theCulex pipiensComplex in North America to Transmit Rift Valley Fever Virus1

“…p. pipiens form molestus occur associated with underground standing water, such as sewers and storm drains, that remain warm year-round, a necessity since this form cannot diapause (Harbach et al 1984). Not surprisingly, in warmer latitudes, such as in southern Europe (Gomes et al 2009(Gomes et al , 2013a, North Africa (Gomes et al 2012), California (Strickman and Fonseca 2012), and in northern Argentina (Micieli et al 2013), aboveground populations of pure Cx. p. pipiens form molestus and/or hybrids with a strong molestus form signature have also been identified.…”

Molecular identification of two Culex (Culex) species of the neotropical region (Diptera: Culicidae)

“…Because of their co-dominance, microsatellites proved to be useful for detecting putative hybrids between closely related species and subspecies of Culex [ 57 , 58 , 59 ]. In the present study, the main difficulty in applying this methodology was the lack of species-specific primers for PCR reactions, and for this reason only three loci could be amplified using primers developed for other species of the genus.…”