Studies on mosquitoes breeding in rock pools on inselbergs around Zaria, northern Nigeria

Rainwater often collects in depressions on rocks to form pools that are ideal breeding sites of mosquito vectors of diseases. Knowledge on the existence of disease vectors in these remote and relatively inaccessible locations could improve epidemiologic understanding and control capabilities. This study identifies mosquito species, their relative abundance and physicochemical characteristics of breeding microhabitats in rock pools on four inselbergs in northern Nigeria. Soup ladle dipper was used to obtain representative samples of larval mosquitoes breeding in 141 rock pools on four inselbergs. Physicochemical parameters (depth, electrical conductivity, pH, surface area, temperature and total dissolved solids) of the pools were determined. Larvae were preserved in 70% alcohol and identified microscopically to species using taxonomic keys. Statistical correlation analysis and ANOVA were used to test the associations between physicochemical parameters and mosquito abundance, and for differences amongst inselbergs. Of 2991 larvae, five species of mosquito distributed in three genera (Anopheles, Aedes and Culex) including Ae. vittatus (92.88%), An. ardensis (0.13%), An. distinctus (1.67%), An. wilsoni (0.13%) and Cx. ingrami (5.18%) bred in the rock pools, Up to five species occurred per pool in various conspecific and heterogeneric combinations. Except for Ae. vittatus, the physicochemical parameters of the pools correlate significantly with species abundance. Ae. vittatus, a potential vector of yellow fever in Nigeria breeds profusely in rock pools on inselbergs around Zaria. For comprehensive vector implication and control, rock pools should be amongst the habitats of focus in yellow fever epidemiology.