SIT works by releasing radiation-sterilized male mosquitoes into an environment to mate with wild female mosquitoes, reducing the size of the population over time as females fail to reproduce, but irradiation of male mosquitoes tends to reduce both their mating competitiveness and their survival rates, undermining the technique’s effectiveness. When males infected with it mate with female mosquitoes that are not infected, their eggs do not hatch. The technique does not work if the female mosquitoes are infected with the same Wolbachia strain and successful mating by mosquitoes that both carry the bacteria undermines the technique by producing more female mosquitoes infected with Wolbachia that are resistant to the process. Preventing the release of Wolbachia-infected female mosquitoes is difficult, with sex sorting usually resulting in a “female contamination rate” of about 0.3 percent. This allowed the team to avoid the sex-screening process and meant they could release significantly more mosquitoes: in some cases more than 160,000 male mosquitoes per hectare per week.

Source: Taipei Times July 18, 2019 16:06 UTC