A deadly fire ant has reached European shores. The insect invasion could wreak havoc

Battaglia remembers the beginning of the infestation, two or three years ago. He saw ant nests in his garden, but these differed from the usual Italian ants. They were smaller, redder, more numerous and they stung. The sting was more painful than he had ever experienced and left small pustules (blister-like sores), the scars of which remained more than a year later.

Around the same time, scientists began investigating reports of a new kind of ant on the island. In 2023, they released their findings: red imported fire ants had established populations in Europe for the first time. They mapped 88 nests in the province of Syracuse, where Avola lies. Unable to pinpoint exactly where or when the ants arrived, after further research they suspected the ants had been present in the area since at least 2017.

In Sicily, an eradication program began in June 2025. Led by the regional government and Italy’s Ministry of the Environment, along with scientists from the University of Catania, it aims to stop the ants from spreading farther into Europe and exterminate the species from the island.

The species’ common name comes from the fact that when it stings, “it has this burning feeling like fire,” said Lucia Zappalà, a professor of entomology (insect studies) at the University of Catania, who is involved in the program. The scientific name is because “it seems not to be beatable, not controllable, not manageable.”

Invicta is Latin for invincible.

As it spreads, the red imported fire ant has wreaked havoc. The species is omnivorous. It preys on native ants, as well as other bugs, reptiles, and amphibians, such as frogs and lizards, and even small mammals. In the US, they have been documented raiding songbird nests, attacking and consuming eggs and young birds.

In Australia, Marni Manning of the National Fire Ant Eradication Program, said that the invasive ants are already having a significant effect on the country’s iconic species. “The koala, a slow-moving animal when it’s on land, is highly vulnerable to the predatory aspects of this ant. We’ve also had pictures of echidnas (spiny anteaters) dead on fire ant nests,” she said.

The ants destroy the roots of plants and seedlings, such as soybeans and hemp, affecting biodiversity and damaging agricultural crops. In China, the red imported fire ant has reduced the yield of mung beans and the ants’ poisonous stings have harmed livestock and farm workers. Yijuan Xu, a professor at South China Agricultural University, said in an email that “some farmers, unable to tolerate red imported fire ant stings, have abandoned their land.”

Attempts at controlling the species have been expensive. In the US, the fire ant is estimated to be responsible for over $6 billion annually in damage repair, medical care and control costs, while Australia has committed 600 million Australian dollars ($400 million) over a four-year period to aid eradication.

Manning said this is a fraction of what it would cost if fire ants continued to spread. Currently the species is mostly contained in the state of Queensland, but according to the program’s projections, left unchecked the invasive ants could infest up to 97% of the country and cost up to 2 billion Australian dollars ($1.3 billion) each year.

Eradication attempt

Sicily is already suffering some of the effects of the infestation. A state-owned nursery in the province of Syracuse has closed and rows of young saplings of native trees, once earmarked for reforestation, are waiting to be destroyed.

When CNN visited, scientists from the University of Catania opened the roots of one plant and a colony of ants erupted from the soil. This highlights the potential danger, said Zappalà, “It can be transported as a hitchhiker on any kind of fruit or plant material.”

The researchers observed that in areas where there is a high density of red imported fire ants, there are often far fewer native ant species present, or none at all. With time, this would influence the entire ecosystem, explained Roberto Catania, a postdoctoral researcher at the University of Catania, disrupting the natural balance and affecting plants and animals that rely on the native insects.

In a war cemetery on the outskirts of Syracuse, the northernmost place the ants have been recorded, nests are rife. The research team, looking to assess the density of the species, put out test tubes containing a slice of frankfurter as bait along the graves. Within half an hour, each one was crawling with red imported fire ants.

The goal of the eradication program, explained Zappalà, is to create a containment boundary from the outside edge of the known infestation and gradually move inward, treating targeted areas. Bait — containing corn grit and soybean oil, which the ants are attracted to, and an insecticide called indoxacarb — is applied to each nest or to localized areas where the ant is present.

The ants take the bait back to the nest, where it is eaten by the queens, helping to destroy the whole colony.

Yet scientists are concerned that with the high density of ants, full extermination may be unlikely. “Eradication is a challenge, especially when the presence of the species is wide,” said Zappalà.

Others fear that it may be too late. “There’s still some hope that they could eliminate them from Sicily,” said entomologist Vargo. “Whether they could do it in time to prevent them from spreading to the mainland (I don’t know).”

Many experts point to New Zealand as an example that proves the importance of early surveillance and monitoring. But the country had an advantage: it already had strict biosecurity rules in place, a history of national surveillance programs for pests and invasive species, and widespread citizen awareness.

“New Zealanders are very aware of introduced predators and what they can do,” said Phil Lester, biology professor at New Zealand’s Victoria University of Wellington. “Biosecurity is a high priority here — we are in the middle of nowhere … and we’re proud of our biodiversity and go to some effort to control invasive species.”

This has not been the case in Italy. Scientists stumbled upon the species potentially years after it was first established and eradication efforts only began two years after official documentation of the species.

Piero Genovesi, chair of the International Union for Conservation of Nature (IUCN) Invasive Species Specialist Group, explained that the red imported fire ant is included in the European Union’s list of top priority invasive alien species and so there is an obligation for all EU countries to apply surveillance efforts and immediately report the ants when they are detected. “This is easy to say, not so easy to practice in the field,” he admitted. Unlike New Zealand, “we don't have a tradition of creating prevention systems for invasive alien species.”

Sicily’s eradication team is appealing to the public to help efforts. It plans to launch a citizen science program, which will help give a more complete understanding of where the ants have spread. “I’m afraid of all those nests that we haven’t found yet that are there in private houses, in private gardens, in orchards,” said Zappalà.

Tip of the iceberg

Sicily is on the front line of Europe’s fire ant invasion. If it fails to contain the spread, more countries will be at risk. Genovesi hopes that the potential danger will spur the rest of the continent into action — leading to stronger biosecurity policies, an increase in prevention efforts and coordinated action.

“Inaction by one country can affect others,” he said.

Giusi Savarino, regional councilor for Sicily’s Department for Territory and Environment, told CNN in a statement that despite the slow detection of the fire ant, he is confident that they will be able to “quickly contain the species’ population” and ultimately achieve eradication within the region.

However, he added that due to the difficulty of detecting the ants at border controls, “it cannot be ruled out that the species is already present in mainland Italy; therefore, Europe’s security regarding the fire ant does not depend solely on the eradication efforts of the Sicilian region.”

The red imported fire ant is just the tip of the iceberg. Invasive alien species are among the top drivers of biodiversity loss and responsible for more than 60% of all global extinctions, according to the IUCN. With globalization and climate change, their spread is rapidly increasing.

But this is an environmental problem the world can fix, said Genovesi: “We don't have clear ideas on how to prevent the extinction of 1 million species, but we do know how we could significantly reduce the impact of invasive alien species. It requires resources, of course, more political will, clear legislation and awareness of the public.”

There is one big advantage in the fight against this feisty fire ant. Its lethal stings and preference to nest in humid, irrigated areas near humans means that its invasions generally do not go unnoticed. Early detection is possible.

If countries are alert and act fast, the “invincible” ants could be defeated.