Morphological studies of Female Simulium damnosum S.I. in Akamkpa Local Government Area, Cross River State, Nigeria IJEN Morphological studies of Female Simulium damnosum s.l. in Akamkpa Local Government Area, Cross River State, Nigeria

This study was carried out between February 2014 and January 2015 to investigate the morphology of Simulium damnosum s.l. populations along Kwa Falls and Rhoko river in Akamkpa Local Government Area of Cross River State, Nigeria, in relation to the strain of Onchocerca volvulus transmitted in the study area. Two fly boys working on shift of 6 hours captured Simulium flies settling on them for blood meals by inverting specimen vials over them. Simulium flies were preserved in 70% ethanol and transported to the Biological Science Laboratory of Cross River University of Technology, Calabar, for entomological studies. Of the 265 Simulium species studied, 29 species were identified as savanna-dwellers, 98 species as transition zone dwellers and 138 species as forest-dwellers. There was significant difference (p<0.001) in the wing tufts colour but no significant difference (p>0.05) between blackflies from these rivers. Mean thorax/antenna ratios of 2.4143, 1.9673, and 2.033 were recorded for savanna dwellers, transition zone dwellers and forest species respectively. Based on the morphology of Simulium damnosum s.l. studied, it could be inferred that there are likely four Simulium sibling species related to Simulium sirbanum, S. squamosum, S. yahense and S. damnosum sensu stricto in the study area.