Advances and challenges in the sterile insect technique: From insect sperm to prototypes

The Sterile Insect Technique (SIT) is an environmentally friendly technique which consists in the mass-rearing, sterilization through ionizing radiation and release of sterile insects in affected areas. Males must then find, mate with wild females, and transfer an ejaculate containing sperm with lethal mutations, which will then hinder the wild female from laying fertile eggs. Most SIT programs utilize gamma rays to sterilize males, however, X rays could provide a viable alternative with greater advantages because they are not produced by nuclear processes, there is no concern on transportation, management or waste of radioactive material. Here, we
present data on the effect of X rays, compared to gamma rays, on sperm quality and female postcopulatory behavior of the Mexican fruit fly, Anastrepha ludens (Diptera: Tephritidae). We also review X ray prototypes that could be used for Tephritid and mosquito irradiation. Furthermore, we discuss innovations for the mass-rearing of Medfly, Ceratitis capitata, at the new Moscamed facility in Mexico. Some of the challenges include rearing in a semi-natural environment and optimizing scaling of production. Finally, we end with future perspectives on how the sterile male ejaculate provides an opportunity to modify wild female behavior, and how SIT could be supported, given its green credentials, and its successful implementation in both developed and developing countries.