Autogeny Expression in Culex Pipiens Complex Populations in Serbia

From a public health perspective, Culex pipiens (the house mosquito) is the most important mosquito species in Serbia. Its confirmed vector competence has enabled the sustained transmission of West Nile virus (WNV) to humans and animals in Serbia for over a decade. Despite this, the species’ biology and ecology remain underexplored: this study aims to help fill that knowledge gap. This research examined autogeny in female mosquitoes and assessed whether the presence of males affects its expression. Larvae of the Cx. pipiens complex were collected from three ditches and two urban street catch basins and reared to adult stage. Experimental subjects included adults emerging from field collections and individuals originating from an autogenous laboratory colony. Female mosquitoes were maintained in cages either with or without males and fed solely on sugar solution (no blood meals), and left undisturbed for five to seven days to permit egg development. No oviposition site was provided. Subsequently, females were dissected and their ovarian development evaluated. Results revealed that, under laboratory conditions, male presence did not affect autogeny expression. After 10-12 days, females contained no eggs in their abdomens, suggesting egg resorption due to the absence of an oviposition opportunity. In field-collected breeding sites, autogeny was rare: only two catch basins and one ditch yielded autogenous females. The highest rate observed was 45% (in a catch basin), while other positive sites recorded rates of 12.5% (catch basin) and 2.15% (ditch). Given the documented coexistence of the pipiens and molestus biotypes within the same breeding sites, hybridization is likely to occur. Hybrids, feeding on both avian and mammalian hosts, are recognized for their role as bridge vectors in transmitting WNV to humans and other mammals, and thus hold considerable public health importance.