Sex ratio distortion and semi-sterility in the progeny of irradiatedGlossina morsitans

Abstract

SUMMARYMaleGlossina morsitanswere subjected to various doses of gamma radiation in air or nitrogen and mated to untreated females. The sex ratio of theF1progeny was biased towards males, and this may be explained by the extra vulnerability to dominant lethal induction that the presence of the largeXchromosome gives to female determining sperms. The mean fertility of theF1progeny was subnormal. This was due to the induction of 50 % sterility in a large proportion ofF1individuals. Cytogenetic examination of the progeny of outcrosses ofF1individuals indicated that in most of the semi-steriles there were translocations involving the large autosomes or theYchromosomes. Almost all the normally fertileF1flies gave only cytogenetically normal progeny. TheF1sex-ratio distortion and semi-sterility would provide a ‘bonus’ in the application of the sterile male technique, which would amount to a 15–50% saving in the releases required to achieve a population control target compared with the requirement if theF1was normal.