Maximizing the Production of Glossina palpalis gambiensis Sterile Males in Mass Rearing by the Optimizing of the Sex Ratio

Abstract

Tsetse flies occur in much of sub-Saharan Africa as vectors of trypanosomes that cause human and animal African trypanosomosis. For its control, the Sterile Insect Technique based on mass rearing is currently used. But the improvement of tsetse productivity in mass rearing requires a better environment condition but also the control of productivity parameters. One of these important parameters is the choice of the ratio of females and males according to the targeted species. The aim of this study was to perform tests for getting the best female to male adults ratios in mass-rearing colonies of Glossina palpalis gambiensis for the purpose of optimizing the yield of sterile males. To achieve this, the mortality and fecundity for various male to female ratios (1:2, 1:3, 1:4, 1:8 and 1:10) on adult tsetse fly in routine rearing over 60 days after emergence was monitored and each experimental batch was replicated five times. Pupae production and fly mortalities were monitored daily except on Sunday. Females of the 1:4 ratio survived longer than those from 1:2 and 1:3 but similar to those from 1:8 and 1:10. The best survival was observed with flies from the ratio 1:10. The highest pupae per initial female per 10 days was observed with the ratio 1:4. The best Glossina palpalis gambiensis male to female sex ratio should be 1:4, due to the higher significant fecundity combined with lower mortality of females, in order to maximize the productivity of the colonies and the yield of male flies that can then devoted to sterile insect technique projects.