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Efforts to combat tiger mosquito using sterilised insects expand in France
More French towns are set to adopt the innovative technique next spring
Published
Sterilisation campaigns against the tiger mosquito (moustique tigre) are spreading in France as another commune decides to tackle the disease-carrying insect.
Conflans-Sainte-Honorine (Yvelines) is set to release batches of sterile male tiger mosquitoes each month between May and October next year, in an attempt to reduce their numbers.
The male mosquitoes - which do not bite humans - are sterilised using x-ray technology, meaning that after breeding with female mosquitoes their unfertilised eggs will not be able to hatch.
This will be the first campaign of its kind to take place in Île-de-France. The campaign is set to last for three years, and cost around €150,000-€200,000.
No official figures have been published about the number of sterile insects they plan to release, but previous campaigns in other areas of France have seen figures in the hundreds of thousands per month.
The town of Bruges (Gironde) is also set to test a similar sterilisation campaign from next spring.
The first sterile mosquito releases took place in mainland France in 2025 in Brive-la-Gaillarde (Corrèze). Similar initiatives have also been carried out in Montpellier, Toulouse, Mions and La Verpillière near Lyon, and Sainte-Eulalie near Bordeaux.
Communes have been working in collaboration with Terratis, a specialist company based in Montpellier that develops technologies to breed sterile insects on a large scale.
In a previous interview with The Connexion, Dr Clélia Oliva from Terratis explained the company’s sterilisation process, and highlighted that common areas for releases include parks, gardens, public squares, airports and cemeteries.
The proliferation of tiger mosquitoes has led to other ingenious methods by communes to curb their numbers.
The mairie in Suresnes (Hauts-de-Seine), for example, recently announced that it was encouraging more bats, a natural predator of the insect, via the installation of bat boxes in the town’s parks and squares.
An invasive, non-native species
Tiger mosquitoes, originally from Asia, are named after the white stripes on their bodies.
They are highly adapted to urban environments and can breed in small amounts of stagnant water, and are present in all French regions.
They are capable of transmitting diseases including dengue, chikungunya and Zika, and are still active despite the arrival of autumn.
Tiger mosquitoes tend to remain close to where they were born, meaning that releasing sterile males in targeted locations can have a significant local effect.
Terratis reported that this technique could reduce mosquito reproduction by 50% within the first year of a campaign - as was the case in Brive-la-Gaillarde. It will not lead to their complete eradication.
As an invasive non-native species, reducing their numbers is not expected to cause ecological harm.
Help to reduce mosquito numbers
The best way to reduce mosquito numbers is to prevent them from breeding to begin with.
As well as communal efforts, such as the sterilisation campaigns, members of the public can take individual action - particularly those who own any outside spaces.
Around 80% of tiger mosquito breeding sites in France are on private property, according to the regional health agency (agence régionale de santé) in Auvergne-Rhône-Alpes.
Measures can include covering rainwater collection systems with mesh, placing sand in flower pots and saucers to prevent water collecting, removing containers where water can gather, and using mosquito traps where appropriate.
It is also important to check for puddles inside homes - under taps, in the bathroom or in damp basements, for example.
This will reduce opportunities for mosquitoes to find stagnant water to lay eggs.
Tiger mosquito sightings can be reported via the Agence nationale de sécurité sanitaire de l'alimentation, de l'environnement et du travail (Anses) website.
