Effects of contamination with wild-type males, virgin females or mated females, on the stability of the T:Y(ωp†)30C genetic sexing strain of Ceratitis capitata (Diptera: Tephritidae)

Abstract

AbstractThe T:Y(ωp†)30c genetic sexing strain of Ceratitis capitata (Wiedemann), which is designed to generate males with brown (wild-type) pupae and females with white pupae, was contaminated artificially in a series of population experiments, to investigate the pattern of breakdown of the strain. The frequency of brown female pupae increased whether contamination was with males, unmated females or mated females, but the frequency of white male pupae increased only after male or mated female contamination. Contamination with either sex, mated or unmated, caused a rise in the overall frequency of brown pupae. A fitness advantage of the ωp† gene, when not attached to the Y chromosome, seemed to be indicated. The sex ratio became distorted in favour of females after contamination with females, mated or unmated, but not after male contamination which caused a temporary increase in males. The experiments revealed evidence of a low frequency of natural recombination between ωp† and the translocation breakpoint on the Y chromosome, shown by the appearance of a small number of white males that could not be attributed to the experimental procedure. These findings are shown to be relevant in determining whether wild type contamination has taken place in mass rearing of this strain for sterile male release.