Characterization of Simulium (Edwardsellum) damnosum s. l. populations from six river systems in Kenya by cellulose acetate electrophoresis

Isoenzyme characterization of the Simulium damnosum Theobald sibling species complex from two widely separated geographical areas in Kenya is presented based on 10 enzymatic loci. Four river systems in Western and Nyanza Provinces, namely, the Yala, Lusumu, Isiukhu and the Nzoia harbouring S. damnosum s.l. were compared among themselves and with S. damnosum s.l. collected from the Thiba and the Nyamindi river systems in the Mt. Kenya area. The two populations were easily separable using PGM, HK and, more than 73% of the time, with PGI. Using the first two enzymatic loci, PGM and HK, all the western Kenya S. damnosum s.l. belong to the same population while those from Mt. Kenya areas belong to a different population. In both geographical zones there was less than 20% qualitative and quantitative polymorphism within infraspecific forms in any given breeding area of S. damnosum s.l. Three enzymes, ME, XDH, and G-6-PDH had isomorphic mobilities for both the Mt. Kenya and western Kenya populations. Four other enzyme/substrate systems tested had no satisfactory resolution as a diagnostic value.