Suppression of Aedes mosquito populations with the boosted sterile insect technique in contrasted environments

Aedes mosquitoes are the vectors of dengue and other arboviruses, which threaten billions of people world-wide. The boosted sterile insect technique (boosted SIT) is a version of SIT where irradiated sterile male also transmit a biocide to wild females. We describe three field trials: one against Aedes aegypti in La Reunion, and two against Aedes albopictus in Spain, all three using pyriproxyfen as a biocide. The relative density of adults in comparison to control sites, decreased from 1.00 to 0.09, 95% credible interval [0.06, 0.15] (La Reunion, July), and to 0.02 [0.01, 0.03] and 0.11 [0.08, 0.16] (Spain, July and October). The success rate, corresponding to the proportion of traps with a suppression over 80%, ranged from 0.43-0.71 in La Reunion, and 0.26-1.00 and 0.50-0.70 in Spain. In one of the sites in Spain, boosted SIT allowed a stronger suppression in 2021 than SIT in 2020 and 2022. This work is in line with model predictions of a better efficiency of boosted SIT in comparison to SIT, together with a partial protection from the invasion of treated areas by fertile females, paving the way for large scale field trials.