One of the most harmful invasive ant species in the world has been spotted in Sicily. It’s the Solenopsis invicta, a red ant with a painful sting originally from South America, and this marks its first sighting in Europe. This was reported in an article published in the journal Current Biology.

Researchers warn that these ants could soon spread throughout the continent, causing severe environmental, health, and economic problems in Italy and beyond. “S. invicta is one of the worst invasive species. It can spread alarmingly,” says lead author Mattia Menchetti from the Institute of Evolutionary Biology in Spain. “Finding it in Italy was a big surprise, but we knew this day would come.”

Commonly known as the imported red ant, the name S. invicta derives from this ant’s most infamous characteristic: its stinger, which causes pain and occasionally can lead to anaphylactic shock. Despite being native to South America, S. invicta has spread rapidly. Human activities have contributed to its spread through maritime trade and the shipment of plant products, allowing it to establish itself in Australia, China, the Caribbean, Mexico, and the United States in less than a century.

The Arrival in the Old Continent

Europe managed to avoid it longer than expected, say the researchers. “Currently, there are numerous ant species establishing themselves in Europe, and the absence of this species was somewhat of a relief,” says Menchetti. “For decades, scientists have feared its arrival. We couldn’t believe our eyes when we saw it.”

After seeing photos taken in Sicily that appeared to depict S. invicta, the researchers made a trip to the region to confirm the identity of the ants and collect samples. They discovered a total of 88 nests in an area of 4.7 hectares in the Saline di Siracusa area at the mouth of the Ciane River, some of which housed thousands of worker ants. Speaking with the local population, researchers learned that people in the Sicilian region had been stung, often for several years.

“The local residents have been experiencing these painful encounters since at least 2019, so the ants have likely been present for some time,” says Menchetti. “And the actual extent of the invaded area is probably larger.” The team suspects that this was not the S. invicta’s first incursion into Europe.