Genetic Variation at Structural Loci in the Glossina morsitans Species Group

Gene diversity was investigated in four taxa of tsetse flies (Diptera: Glossinidae) including Glossina morsitans morsitans, G. m. centralis, G. swynnertoni, and G. pallidipes. Histochemical tests were performed for 35–46 isozymes. Polymorphic loci were 20% in G. morsitans morsitans, 32% in G. m. centralis, 17.6% in G. swynnertoni, and 26% in G. pallidipes. Mean heterozygosities among all loci were 6.6% in G. morsitans morsitans, 6.0% in G. m. centralis, 7.1% in G. swynnertoni, and 6.8% in G. pallidipes. Allozyme gene diversities were considerably less than those reported for many Diptera. The low gene diversities are probably related to small effective population sizes.