Mating harassment may boost the effectiveness of the sterile insect technique for Aedes mosquitoes

Abstract The sterile insect technique (SIT) is based on the overflooding of a target population with released sterile males inducing sterility in the wild female population. The SIT has proven to be effective against several insect pest species of agricultural and veterinary importance and is under development for Aedes mosquitoes. Here, we show that the release of sterile males in high sterile male to wild female ratios may also impact the target female population through mating harassment. Under laboratory conditions, male to female ratios above 50 to 1 reduced the longevity of female Aedes mosquitoes by reducing their feeding success. Under semi-field conditions, blood uptake of females from an artificial host and biting rates on humans were also strongly reduced. Finally, in a field SIT trial conducted in a 1.17 ha area in China, the female biting rate was reduced by 80%, concurrent to a reduction of female mosquito density of 40% due to the swarming of males around humans attempting to mate with the female mosquitoes. This suggests that the SIT does not only suppress mosquito vector populations through the induction of sterility, but might also reduce disease transmission due to increased female mortality and lower host contact.