Sexual Sterilization of Screw-Worm Flies by a Peroral Chemosterilant: Quantitative Aspects and Relation to Pretreatment Starvation123

Abstract

The relationship of the quantity of ingested uredepa (ethyl [bis (1-aziridinyl) phosphinyl]carbamate) to the induction of sexual sterility in screw-worm flies, Cochliomyia hominivorax (Coquerel), was studied. Also, related studies were made of the amount of sugar syrup eaten in 1 meal, the camparative food value of sugar syrup and honey, the need for protein in the adult diet, and the effects of pretreatment starvation on the action of the chemosterilant. Sugar syrup and honey were equivalent carbohydrates, and protein was unnecessary for adult subsistence and reproduction. Flies 24 and 48 hours old, irrespective of sex, ingested 2-3 times more sugar syrup than 0- to 4-hour-old flies. Newly emerged flies accepted sugar syrup containing as much as 1% uredepa as well as they accepted untreated sugar syrup. Males passed from fertility to sterility over a narrow range of doses (6-11 /μg) in comparison with a very wide range for females (5-72 /μg) and were about 6.5 times more susceptible to chemosterilant induction of sterility than females on the basis of total dose consumed. The activity of substerilizing concentrations of uredepa was markedly augmented by pretreatment starvation for 24 hours or more: complete sterility was induced in either sex.