Assessment of Man-Biting Rate and Gonotrophic Cycle of Mosquitoes in Orashi Region of Rivers State, Nigeria
By Wisdom U. G., Oghanri, S. U, Iwuorie, C. G.
This study assessed the temporal and spatial dynamics of mosquito biting activity and gonotrophic behaviour across selected communities in the Orashi Region of Rivers State, Nigeria. A total of 1,768 mosquitoes comprising key vector genera were analysed to determine monthly variations in the Man-Biting Rate (MBR), the gonotrophic cycle of Anopheles species, and spatial biting pressure across five communities. Monthly trends showed pronounced seasonal fluctuations, with the highest MBR recorded in April (386) and March (368), classified as Very High, reflecting optimal breeding conditions during the late dry to early rainy transitional period. High biting rates also occurred in September (358) and October (343), corresponding to early rainy season abundance. Moderate and low biting activity in November (222) and December (118), respectively, indicated reduced breeding associated with declining rainfall and the onset of the dry season. Analysis of the Anopheles population revealed corresponding shifts in gonotrophic activity. Spatial assessment demonstrated substantial community-level variation in biting pressure. Ahoada recorded the highest overall mosquito density (600), indicating Very High biting pressure, followed by Erema (536) and Oboburu (517). Spatial distribution of malaria vectors showed a similar pattern, with Anopheles abundance highest in Ahoada (191), suggesting elevated malaria transmission risk. Culex distribution indicated highest densities in Erema (241) and Ahoada (235), highlighting significant nuisance biting and potential filariasis risk. Aedes populations were comparatively low, with Omoku (17) showing slightly elevated arboviral risk. Conclusively, the findings demonstrate that mosquito abundance, biting rates, and reproductive activity exhibit strong seasonal patterns and spatial heterogeneity across communities.