Large indoor cage study of the suppression of stable Aedes aegypti populations by the release of thiotepa-sterilised males

The sterile insect technique (SIT) is a promising pest control method in terms ofefficacy and environmental compatibility. In this study, we determined the efficacyof thiotepa-sterilised males in reducing the target Aedes aegyptipopulations. Treated male pupae were released weekly into large laboratorycages at a constant ratio of either 5:1 or 2:1 sterile-to-fertile males. A two-to-onerelease ratio reduced the hatch rate of eggs laid in the cage by approximately athird and reduced the adult catch rate by approximately a quarter, but a 5:1 releasedrove the population to elimination after 15 weeks of release. These results indicatethat thiotepa exposure is an effective means of sterilising Ae. aegyptiand males thus treated are able to reduce the reproductive capacity of astable population under laboratory conditions. Further testing of the method insemi-field enclosures is required to evaluate the mating competitiveness of sterilemales when exposed to natural environmental conditions. If proven effective, SITusing thiotepa-sterilised males may be incorporated into an integrated programme ofvector control to combat dengue in Cuba.