Climate change fuels spread of invasive ants to European shores

One of the world’s most destructive invasive species, the red imported fire ant, has reached Europe for the first time — landing on the Italian island of Sicily a few years ago. Scientists warn the invasion could have devastating consequences for biodiversity, agriculture, and public health across the continent.

In June 2025, Sicily launched an emergency eradication program led by the regional government, Italy’s Ministry of the Environment, and researchers from the University of Catania. The operation aims to halt the ants’ spread and wipe them out before they reach mainland Europe, CNN reported.

Dominant species in new territories

The ants, known scientifically as Solenopsis invicta, are infamous for their painful sting — “it has this burning feeling like fire,” said Lucia Zappalà, a professor of entomology at the University of Catania. The name invicta comes from Latin, meaning “invincible.”

The invasive species poses a severe threat to crops and ecosystems, destroying the roots of plants such as soybeans and hemp.

“It can be transported as a hitchhiker on any kind of fruit or plant material,” Zappalà warned.

Aggressive and resilient, the ants swarm their prey and inject venom repeatedly, killing small animals and sometimes livestock. Human stings can be painful and even cause severe allergic reactions.

Native to Latin America, the ants spread to the US in the 1930s, likely via contaminated soil in cargo ships. From there, they colonized the Caribbean, Australia, New Zealand, Taiwan, and China in the 1990s. Their expansion has caused billions in damage — over $6 billion annually in the US alone for medical treatment, crop loss, and control efforts.

Sicily is already feeling the impact. In the province of Syracuse, a state-owned nursery has been forced to close after infestations were discovered. When University of Catania scientists examined the roots of young saplings, “a colony of ants erupted from the soil,” CNN reported.

Exhausting task of containing spread

The eradication team is working outward from the known infestation area, treating soil and vegetation. Yet challenges remain.

“Eradication is a challenge, especially when the presence of the species is wide,” said Zappalà. Entomologist Vargo echoed the concern: “There’s still some hope that they could eliminate them from Sicily. Whether they could do it in time to prevent them from spreading to the mainland (I don’t know).”

New Zealand remains the only country to have successfully eradicated the species.

“New Zealanders are very aware of introduced predators and what they can do,” said Phil Lester, biology professor at 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.”

By contrast, Italy detected the ants potentially years after they first arrived.

“This is easy to say, not so easy to practice in the field,” admitted Piero Genovesi, chair of the IUCN Invasive Species Specialist Group. “We don’t have a tradition of creating prevention systems for invasive alien species.”

Now, Sicilian authorities are calling on citizens to help locate hidden colonies. A new “citizen science” program will map sightings to track the 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,” Zappalà said.

With climate change creating warmer conditions across Europe, researchers warn that as much as 7 percent of the continent could become suitable for fire ant colonies — unless Sicily’s containment efforts succeed.

By Nazrin Sadigova