Electric ants infestations spread in south of France

The number of known electric ant infestations in France has jumped from one to eight in just four years, with most of them located in the Var department, according to a specialist in the field. 

Seven sites have so far been found in the Var, with the latest identified site in the neighbouring department of Bouches-du-Rhône.

The invasive species, Wasmannia auropunctata, was first detected in Toulon in 2022. The sites in the Var are in Toulon, La Croix-Valmer, two sites in Cavalaire-sur-Mer, Sainte-Maxime, Hyères and La Seyne-sur-Mer. The eighth site is in Carry-le-Rouet, west of Marseille.

Five of the eight sites were identified following the launch of the Vigi-Sud reporting platform in May 2026, which allows people to submit photographs of suspected electric ants for identification.

“Given their size, these infestations have usually been there for several years by the time we discover them,” Luc Gomel, an ant specialist who is involved in research, treatment and monitoring efforts alongside other researchers and public authorities, told The Connexion.

Electric ants pose a threat because of their painful stings, which can sometimes cause allergic reactions. They also negatively impact local ecosystems, displacing native ants and preying on other insects, lizards and even baby birds.

How did the ants arrive?

Researchers believe the ants were introduced through contaminated potted plants, but the precise route remains unknown.

The affected sites are generally residential areas with gardens, including properties where exotic plants may have been introduced.

A scientific study co-authored by Olivier Blight of Avignon University examined the genetic relationships between electric ant populations in southern Europe and the eastern Mediterranean. 

Native to South America, the species appears to have reached France through a secondary introduction linked to Israel or Cyprus, according to their findings. 

“We don't know which plants brought the ants to the properties that are infested,” Mr Gomel said, explaining that it could be difficult to establish the original source because a colony might have spread across an entire residential development before anyone noticed it.

Can electric ants be eradicated?

Treatment operations have taken place at sites in the Var, with researchers working alongside FREDON PACA, a regional plant health network, which coordinates field operations. Toxic bait is set during the warmer months (from May to October) when the ants are active.

The bait is designed to be carried back to the nest and shared with other ants. It contains an insecticide mixed with an attractive food source. 

“Only 2% to 5% of the colony are foragers (worker ants),” Mr Gomel explained. “The ants we see outside are only a small part of the population.”

This is why the bait acts slowly enough for the foraging ants to take it back to the nest and distribute it to the rest of the colony, including the queen, before the poison takes effect.

The treatment strategy has been adapted since operations began in 2025. Bait dispensers are used around houses and terraces, while the product is also spread across suitable green spaces to increase the likelihood of ants encountering it.

Mr Gomel said populations had fallen considerably in treated areas, with very few ants remaining in some locations. However, he said they cannot celebrate just yet.

“As we reach autumn and winter, the ants become less active. When they disappear at the end of summer, we cannot be sure that it is because of the treatment; it could simply be the cold.”

Researchers expect to assess the results more reliably in spring 2027, when the ants become active again. At least two years of treatment may be needed to determine whether eradication is possible.

The product currently being used is imported from Australia under a special authorisation and is not generally available for private individuals to purchase in Europe.

What should you do if you spot the ant?

Electric ants are tiny and can be difficult to distinguish from other species. Their stings can cause considerable discomfort; several ants can sting a person at the same time.

“People often don't even see them because they are so small. They wonder what has stung them without understanding what it is,” Mr Gomel said.

People who believe they have found electric ants can report them through the Vigi-Sud platform, submitting photographs and information about where they were found.

Residents should not attempt to eliminate an infestation themselves using ordinary ant products. According to Mr Gomel, it is better to report it via FREDON PACA or at the Vigi-Sud platform.

“If you get rid of the ants in one garden but the surrounding gardens are still infested, within a year or two you will have the same level of infestation again,” Mr Gomel said.

He said the only effective approach currently available was coordinated treatment across the affected area.

“It's a collective fight against invasive ants, not just against this particular species.”