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

Abstract

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

Aedes aegyptilines for combined sterile insect technique and incompatible insect technique applications: the importance of host genomic background

“…These methods aim either at replacing a target population with a strain having reduced vector competence or at suppressing an Ae. aegypti natural population below the threshold required for disease transmission (Hoffmann et al, 2011; Bourtzis et al, 2014, 2016; Carvalho et al, 2014; Gato et al, 2014; Lees et al, 2015). Both the replacement and the suppression methods have pros and cons (for a brief review see Bourtzis et al, 2016).…”

Sterile Insect Technique: Successful Suppression of Aedes Aegypti Field Population in Cuba

“…Nevertheless, a previous study performed in our lab showed that the weekly release of chemosterilized males at a 5:1 ratio with the fertile males was sufficient to eliminate a caged population of Ae. aegypti within 15 weeks [18]. Certainly, the trials of SIT suppression of mosquito-caged populations should be interpreted carefully, but gives gross evidences of the efficacy of the technique, as part of the progressive, stepwise evaluation of sterile mosquitoes [39].…”

“…Progressive assessment of SIT from laboratory to large cages performed prior to the present study is valuable because it allows for systematic assessment of possible effects on mosquito survival and performance under conditions increasingly more natural [18,19].…”

Chemosterilants for Control of Insects and Insect Vectors of Disease

“…[9c,29] Recently in the face of impinging threats from Dengue, Chikungunga and Zika virus, mass release of aziridine-sterilized males has been revived as a part of an integrated program for control of Aedes vectors in Cuba. [30] …”