Cytotaxonomic study of the larvae of blackfly (Diptera: Simuliidae) from River-Ose, Ondo State, Nigeria

A study of the cytotaxonomy of the larvae of blackfly was undertaken at three sites, Imeri A, Imeri B, and Ose-oba, along River Ose in Ondo State, Nigeria. Based on the morphology of the larvae and the resultant pupae, three species of blackflies were identified. These included Simulium damnosum complex, Simulium alcocki, and one yet to be identified (YI). Investigations on the polytene chromosomes from the salivary glands of each of these species revealed that the S. damnosum complex comprises of three cytospecies identified as Simulium squamosum, Simulium damnosum s.s, and Simulium sirbanum. The Simulium alcocki was also found to be a complex of sibling species but the YI remained as a single species. There was no significant difference between the distribution of S. damnosum complex and S. alcocki. However, these two species were different from the YI in occurrence. Results of the present study which is in conformity with earlier reports suggest that the study area (River-Ose) has been and is still a good breeding site for S. damnosum and S. alcocki species of black flies. Key words: Simulium damnosum, Simulium alcocki, ‘yet to be identified species’ (YI), sibling species.