Correlation between physicochemical parameters and larval abundance of Culex quinquefasciatus Say in Lagos State, Nigeria

Mosquito breeding habitats play an important role in determining adult mosquitoes’ abundance and distribution. This study assessed the impact of physicochemical parameters of breeding water on Culex quinquefasciatus larval abundance. A larval survey was conducted in Epe, Eti-Osa, Kosofe, and Ojo local government areas (LGAs) of Lagos state. Emerged adults of Culex mosquitoes were identified. Members of the Cx. pipiens complex were identified into subspecies using polymerase chain reaction. Physicochemical parameters of water from larval sampling sites were analyzed using standard techniques. Six Culex species; Cx. quinquefasciatus, Cx. decens, Cx. nebulosus, Cx. cinereus, Cx. tigripes and Cx. duttoni were encountered. Cx. pipiens quinquefasciatus was the only member of the pipiens complex. Breeding habitat in Kosofe recorded the highest electrical conductivity, total dissolved solids (TDS), and nutrients followed by Ojo, Eti-Osa and then Epe. Larval densities were found to have significant relationship with ammonia (r = 0.507, p = 0.027) and sulfate (r = –0.539, p = 0.017) contents of the breeding habitats. The study revealed that Cx. p. quinquefasciatus is the most dominant and only member of the Cx. pipiens complex. Ammonia and sulfate have a significant impact on the abundance of Cx. quinquefasciatus immature stages. Manipulation of these two parameters could make Culex breeding water less suitable in the study areas.