Seasonal abundance and larval habitats characterization of mosquito species in Lagos State, Nigeria

Abstract

The knowledge of the ecology and abundance of mosquito is important in determining the potential risk of exposure to mosquito-borne diseases and the appropriate control measure to effectively reduce the mosquito population. A survey was carried out in four Local Government Areas (LGAs) of Lagos State, Nigeria for one year to determine the abundance, diversity, and larval habitat characteristics of mosquito. Larvae were collected using WHO standard methods, the physiochemical characteristics of the habitats were recorded, the larvae were reared to adults and identified using morphological identification keys and molecular assays. Adult mosquitoes were also collected outdoor using a trap with octanol attractant. Five species belonging to 3 genera were collected and identified as Anopheles gambiae complex, Anopheles funestus complex, Culex quinquefasciatus, Aedes aegypti, and Aedes albopictus. Cx quinquefasciatus (37.7%) is the most abundant followed by Ae aegypti (31.3%) and An. gambiae s.l. (26.9%) while Ae. albopictus (1.9%) is the least abundant. The larval abundance within the different species showed a high level of statistical significance (P<0.001). Simpson's index was found to range from 0.6751 to 0.6926 for all the sampled locations while the Shannon index ranges from 1.187 to 1.242 and Evenness ranges from 0.6566 to 0.7134. The average physiochemical parameter of the water bodies harboring the mosquito larvae includes pH ranging from 7.2 ± 0.1 to 7.7 ± 0.2, Conductivity ranging from 0.35±0.2 to 0.83±0.46, temperature ranging from 28.7 ± 0.65 to 31.3 ± 0.71, and TDS ranging from 330±158.4 to 571.5 ± 320. An increase in the global temperature as a result of climate change could have an effect on temperature and other physiochemical parameters of mosquito larval habitats, thereby altering the duration of their metamorphosis, subsequently an upsurge in adult mosquito abundance leading potential outbreak of mosquito-borne diseases.