Influence of Ecological Setting on Occurrence of Artificial Container-breeding Vector Mosquito Species (Diptera: Culicidae) and Oviposition Attraction to Mineral Salts in Larval Habitats, in Minna, North-central Nigeria

Abstract

The peculiar challenges associated with mosquito vector control in developing urban areas, occasioned by the complex heterogeneity in vector behaviour and population dynamics, informed this study to elucidate the influence of ecotype on Mosquito species occurrence and responses to presence of mineral salts in oviposition sites. Two distinct ecotypes namely, semi-mineral and Urban, were selected as ovitrap stations, in Minna, Nigeria. In addition to the control experiment, adequately replicated ovitraps enriched with individual and combinations of nitrates, sulphates and phosphates were setup in the two ecotype sites and monitored for mosquito oviposition activities. The results indicated significantly (P<0.05) lower number of species and aggregate Mosquito densities in the urban (Mean=17.14±4.52 larvae/ovitrap) than semi-rural ecotype (21.76±3.93 larvae/ovitrap). While, three mosquito species: Aedes aegypti, Culex p. pipiens and Cx. restuans, were common to both ecotypes, additional three species namely; Anopheles quadrimaculatus, Cx. Tarasalis and Cx. quinquefasciatus were encountered in the semi-rural ecotype, though in low densities. Significantly higher larval densities were recorded in ovitraps enriched with mineral salts (range= 19.75±4.57 to 24.25±4.62 larvae/ovitrap) than the control (14.50±4.86 larvae/ovitrap). While, Nitrate ovitraps yielded the highest number of larvae (23.50±7.39 larvae/ovitrap) among the individual mineral saltenriched ovitraps, and closely rivalled those containing combination of all three salts. The individual mosquito species demonstrated significant preferences for certain lone/single or combined salts-ovitraps. These findings revealed significant spatial heterogeneity in cosmopolitan mosquito population behaviour; and calls for the incorporation of diverse species-and ecotype-sensitive tools in mosquito vector control programs in such human communities.