aelimin-mosquito-population-update-2026

Male mosquito releases are based on two innovative and environmentally friendly techniques:

• The Incompatible Insect Technique (IIT), which consists of releasing male Aedes polynesiensis mosquitoes carrying a symbiotic bacterium (Wolbachia) that renders them incompatible with females of their own species on a weekly basis;
• The Sterile Insect Technique (SIT), launched in 2025 in response to the emergence of Aedes aegypti nuisances, based on the weekly release of males sterilized by X-rays.

The mating of female mosquitoes with incompatible (Ae. polynesiensis) or sterile (Ae. aegypti) males prevents the fertilization of their eggs, leading to the collapse of the mosquito population.

Summary of field activities

Interventions took place every week, Monday to Friday, on the motu Onetahi. Weekly activities carried out by our field agent included:

• Regular entomological monitoring, including trap surveillance
• Release of incompatible male mosquitoes (IIT) Aedes polynesiensis
• Release of sterile male mosquitoes (SIT) Aedes aegypti
• Larval breeding site surveys

Additional activities were also carried out on an occasional basis:

• A specific reinforced inspection mission of larval breeding sites, conducted by other ILM agents in late February 2026
• An information and awareness session on the AeLIMIN+ program for a group of RSMA visitors

Preliminary results

Field observations indicate a predominance of Aedes polynesiensis in our traps over Aedes aegypti and Culex quinquefasciatus on Onetahi. As part of the mosquito control effort, 76,000 incompatible Ae. polynesiensis males and 20,000 sterile Ae. aegypti males were released on Onetahi between mid-February and mid-March 2026.

The reinforced larval breeding site inspection confirmed the positive effect of the training and awareness actions conducted in April 2025. Concrete breeding site prevention efforts were observed among hotel staff, notably the storage of equipment away from their living areas. However, numerous larval breeding sites were still recorded on Onetahi, all linked to human activities. Two mosquito species were identified, with a predominance of Aedes polynesiensis over Aedes aegypti. The persistence of these larval breeding sites reduces the chances of achieving the lasting elimination of mosquitoes on Onetahi targeted by the IIT and SIT male releases. It is therefore essential to limit the creation of these sites in order to enhance the effectiveness of the IIT and SIT techniques.

A group of RSMA cadets present on Tetiaroa in March 2026 had the opportunity to attend and participate in a demonstration of incompatible male mosquito releases. The group showed great interest and appreciation for the ecological approach of the AeLIMIN+ program, particularly its avoidance of insecticide spraying.

Perspectives

The AeLIMIN+ program continues with:

• The recruitment of an additional ILM field agent to strengthen the team
• The extension of the entomological monitoring network to Honuea
• The continuation of weekly inspections and sterile and incompatible male mosquito releases on Onetahi
• A new vector control (VCC) awareness and training session for on-site staff referents, led by ILM agents