Population characterization of Culex quinquefasciatus (Diptera:Culicidae): molecular, karyotypic and morphometric aspects

Abstract

Culex quinquefasciatus is a culicid of great medical importance in the world. This species is the main vector of bancroftian filariosis in the Neotropics, and can also transmit arboviruses among animals and humans, such as the West Nile Virus (WNV), the ethiologic agent of a severe encephalitis. This mosquito has synanthropic habits, is capable of living in polluted areas in the cities, and may develop resistance to some inseticides. Owing to its medical relevance of Cx. quinquefasciatus, several attempts of elimination and populational control have been tried. In general, a limiting factor to such methods is the microevolutionary processes of insects, through which they develop tolerance to insecticides and pollution. Hence, microevolutionary studies are a central issue in medical entomology. Microevolutionary studies usually begin by populational characterization throughout geographical transects. As with other culicids of medical importance, population genetics, populational differentiation, and inseticide tolerance of Cx. quinquefasciatus has been studied in many regions of the world. Nevertheless, such studies involving Cx. quinquefasciatus are quite scarce in Brazil. In the city of São Paulo (São Paulo State), there is a population of Cx. quinquefasciatus in a urban area near the Pinheiros river which lives under regular applications of piretroid adulticides as well. In another county of the state of São Paulo, Pariquera-Açu (~150km away from the capital), there is a population inhabitting a semi-rural environment free of pollution insecticides. It is still unknown whether there are genetic/morphological differences or gene flow between those two localities or not. In order to test these hypotheses, the two populations will be compared through different biological tools, which are so far admittedly useful in populational characterization: a) chromosomic characters; b) aspects within the ribosomal DNA; c) wing morphometrics. We aim to identify biological variations that may have any evolutionary importance for this species, which could contribute to improvement of populational control methods. (AU)