Diversity and Abundance of Anopheles (Diptera: Culicidae) Species Complex in some Selected Settlements in Ogbomoso Local Government Area of Oyo-State, Nigeria

Background: It is part of efforts of every passionate government in Africa to reduce, if not eliminate morbidity and mortality due to malaria being transmitted by female anopheles mosquito. Part of this struggle is the malaria indicator survey annually conducted by the Federal Bureau of Statistics (FBS) in Nigeria. It therefore important to communicate community based investigation and communication of entomological data vital for malaria control using appropriate statistical tools. This study generally aims to investigate seasonal abundance of Anopheles mosquito species and their compositions in some selected human settlements. The specific objective is to determine which particular specie of such Anopheles mosquitoes are most abundant and which of the human settlements requires most intervention due to high prevalence of such Anopheles. Methods: Mosquito collection was made once per week indoor between 5:30hr to 7:00hr and 20:00hr to 22:00hr in rooms for twelve months using insecticide spray technique. Adult Mosquitoes from the knock down effect were collected and identified to species and species complex level using keys described by Gillett, Gillies and Coetzee. Two sample test of proportion was adopted to test for significant difference between species occurrence. The Friedman rank sum test was utilized to determine whether or not there exists a statistically detectable difference in abundance of the four species of anopheles mosquitoes in the seven study wards and whether the seven study ward significantly differ in their composition of the four species of anopheles complex. Results: At 5% significance level (α=0.05), the test revealed with p-values 0.0001 and 0.0005 that there is statistically detectable difference among median abundance of the four Anopheles species. An. gambiae s.l. had the highest median (3006) abundance, followed by An. arabiensis (834.5), An. rufipes (608) and An. funestus (471), respectively. However, Akata ward had the largest median composition (812) of the mosquito species followed by Lagbedu ward (786). Alapata ward rank third in terms of median abundance (739.5). Ibapon and Ilogbo wards had approximately the same median Anopheles composition of 714 out of the total of 35,974. Arowomole ward had the least median composition (698). However, most mosquito species (6822) was collected in October and the least (252) in February. Conclusion: Identifying human activities and practices that promote mosquito breeding by communities themselves, identifying and selecting culturally appropriate mosquito control techniques, and the initiation of actions aimed at controlling mosquito abundance are among community directed and self-reliant coping strategies envisaged. Among such includes Long-Lasting Insecticide Treated Bednets, (LLITNs) alongside with Indoor residual spray and most importantly the practice of Larval Source Management (LSM) (Larviciding) in the study areas.