Relative Abundance and Seasonal Distribution of Adult Mosquito Species in Offa, Kwara State, Nigeria.

The composition and seasonal population dynamics of adult mosquitoes in Offa were studied from Jan. 2001 to Dec. 2002 using human baits. Average monthly rainfall, relative humidity, and temperature were obtained from the local weather station and correlated with mosquito abundance. An annual average of 13,063 specimens belonging to five species namely: Aedes cumminsii (Theobald) (41.97%), Anopheles gambiae (Gilies) (23.10%), An. funestus (Gilies) (17.63%), Culex pipiens fatigans (Linnaeus) (14.87%) and Ae. aegypti (Linnaeus) (2.43%) were collected. The highest monthly total collection (100.90 mosquitoes/man/night) was in Aug. and the least (10.51) was in Mar. Significantly higher (ta =0.05) number of mosquitoes was collected in the rainy season (55.48 mosquitoes/man/night) compared to the dry season (14.35). Mosquito abundance was significantly and positively correlated with rainfall (r= 0.70) and relative humidity (r = 0.74) but was negatively and significantly correlated with temperature (r = -0.66). The implications for public health of the occurrence of the mosquito species as well as significance of the correlations of mosquito abundance with climatic variable in planning control measures were discussed.