RADIATION STERILIZATION AND EFFECT OF MULTIPLE MATING OF FEMALES IN GLOSSINA AUSTENI

Adult males of the tsetse species Glossina austeni were irradiated with gamma rays and mated to untreated females. The relationship of dosage to percentage of sperm with induced dominant lethals was established. Individual females were mated to both a sterilized and a fertile male and it was found that sperm from whichever mating was made first was used predominantly, but not exclusively, for fertilization. Sterile and fertile sperm were equally competitive for fertilization, but the fertility/unit time of the females mated to both types of male was just significantly higher than would have been expected on the basis of the relative number of eggs fertilized by each type of sperm. This is explained by the fact that the early death of an embryo in the uterus leads to a 2-day advancement in the time of the next ovulation. It is concluded that the extent to which this consequence of viviparous reproduction would reduce the efficiency of the sterile male method against tsetse flies would be relatively trivial. © 1968.