Production and shipment of wolbachia-infected eggs allows the control of aedes albopictus through the incompatible insect technique on a remote island

Climate and land-use changes are accelerating the spread of the mosquito Aedes albopictus, a major arbovirus vector, leading to the emergence and autochthonous transmission of dengue or chikungunya viruses in temperate regions such as Italy and France. This has prompted the development of alternative control strategies to counteract growing insecticide resistance. The Incompatible Insect Technique (IIT) uses mass releases of Wolbachia-infected males that sterilize wild females through Cytoplasmic Incompatibility (CI). We conducted a six-month IIT suppression trial on a remote island in the Western Indian Ocean using a novel Aedes albopictus line with a single Wolbachia infection inducing bi-directional CI. This ensures both released males and accidentally released females are incompatible, avoiding population replacement, a common limitation of standard IIT. The trial was conducted under operational conditions, with release numbers adjusted to wild population densities. Eggs were produced in a central insectary over 1000 km away, shipped by plane and boat to the release site. Our results show: (i) over 95% suppression within a few weeks of treatment, (ii) effective prevention of population replacement, and (iii) successful long-distance egg shipment. These findings support the feasibility, scalability, and field-readiness of this environmentally friendly vector control approach.