Reproductive status of a wild population of Glossina tachinoides Westwood (Diptera: Glossinidae)

Abstract

Data on the reproductive capacity of a wild population of female Glossina could indicate whether a population is under stress or is likely to collapse. Such data are of primary importance in a tsetse control programme involving the use of the Sterile Insect Technique. A total of 2,176 Glossina tachinoides were collected using Challier and Laveissiere traps. Out of this, 50.28 percent (i.e. 1,094) were females. Three hundred females (27.4 percent of the total females) were examined for the occurrence of mating scars and were dissected for an evaluation of follicular development, spermathecal filling and uterine content. The results showed that 68 percent of the females were parous, 82 percent of the total females or 96.5 percent of the females older than 10 days were inseminated with motile sperm and 18 percent were virgin. Three percent of the females had two pairs of mating scars indicating that they had mated twice and 2.7 percent showed evidence of reproductive abnormality which suggested abortion. The low incidence of reproductive abnormality in this species indicates that the population was well fed, the female were reproducing normally and there was no evidence of adverse stress conditions often imposed on the species by the environment.