Reproductive abnormalities in the tsetse fly, Glossina morsitans orientalis Vanderplank, caused by a maternally acting toxicant in rabbit food

A laboratory colony of Glossina morsitans orientalis Vanderplank had been kept successfully in Edinburgh for 18 months, when reproduction ceased because of a high incidence of abortion and follicular degeneration. A comparison of these flies with imported Bristol-bred flies showed that the latter reproduced well under identical conditions, but since Edinburgh-bred progeny of imported flies also showed poor reproduction, a genetic difference between the two populations could be ruled out. Comparisons of the progeny of flies fed on human and rabbit blood, and of the progeny of flies fed on rabbits maintained on different diets, produced strong biological evidence for a toxicant in one of the diets which produced reproductive abnormalities in the Ft generation of flies. The trouble was thus traced to a change in rabbit diet which took place about a month before the appearance of the reproductive disorders. It is suggested that the toxicant, which remains unidentified, is concentrated by the parent female in the accessory gland secretion and thereby incorporated into larval tissues during intra-uterine development.