Army of Hundreds of Millions of Ants Colonizes Beach

A beach in France is the latest stronghold to have been invaded by millions of tiny insects, wrecking the local ecosystem.

Ants have colonized the dunes of a beach in the town of Mauguio-Carnon, on the outskirts of Montpellier. They have also been found taking over other areas of the country, including Lyon, Bordeaux, Corsica, and Strasbourg, as well as other countries in Europe, such as the Netherlands, Italy, and Switzerland.

"It is estimated that there are at least a few hundred million ants in this entire nest, which is approximately 800 meters long," Luc Gomel, an ant specialist at Paul Valéry University, told local news outlet France 3.

"For usual ants, the number varies from a few hundred to only tens of thousands. Here, we are looking at much higher numbers," he said. "These ants, they have such a teeming mass, such an overpopulation, that they supplant all other species of ants with which they may be in competition. They can have an impact on other species of insects that they seek to attack in order to consume them. By domino effect, there may also be impacts on certain plants."

These ants, Tapinoma magnum, are an invasive species in France, outcompeting and decimating local ant species as they rapidly reproduce and spread across the continent. Native to the Mediterranean basin and North Africa, these ants are small, black, and non-biting, measuring less than 0.1 inches, and smell like rancid butter.

"The Tapinoma magnum was only identified in 2017," Jean-Yves Bichaton, responsible for the PACA-Corsica region of the French Observatory of Biodiversity (OFB), told DayFREuro. "Before that, it was actually confused with three other ants: Tapinoma nigerrimum, Tapinoma darioi, and Tapinoma ibericum."

"It probably crossed the Mediterranean thanks to man, but there is no way to verify it," he said.

These ants are such a problem because they eat a variety of plants, including fruit trees, and kill other species that help to regulate local ecosystems, like spiders.

"A colony of Tapinoma magnum has several hundred, even several thousand queens, and this from the creation of the colony," Bichaton said.

In attempting to get rid of these invasive ants, many people actually make the problem worse.

"Most people aggravate the problem," Cyril Berquier, an entomologist at the Corsican Environment Office, told France 3 in 2020. "They often use products that destroy the local ants that were still there. They will kill a few Tapinoma but the year, according to them, they will have twice as many."

This is because Tapinoma magnum ants thrive in "degraded" environments with low biodiversity, which is exactly what is created after the use of insecticide.

"If you really have a big Tapinoma problem, you may need to treat in a more localized manner, identify where the anthills are—often at the edge of the concrete—and treat only this area so as not to attack other ants," Berquier said. "If you mow your lawn short, all the time, you also reduce the diversity of ants and you encourage Tapinoma, you promote drought which itself maintains its development."

"Know your enemy (Tapinoma magnum), favor your allies (biodiversity)."

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