Marching One By One: First Red Fire Ant Nests in Europe Found in Sicily

Several red fire ant colonies have been found recently in northern Sicily, and a study published Monday in in Current Biology explains the extent of their spread and how they likely established themselves on a new continent.

“S. invicta is one of the worst invasive species. It can spread alarmingly quickly,” lead study author Mattia Menchetti, a researcher at the Institute of Evolutionary Biology in Spain, told US media.

According to their report, 88 nests have already been found spread across 5 hectares (12.4 acres) in the Syracuse suburbs, on Sicily's southeastern corner. DNA analysis revealed the ants had come from either the United States or from China, where they have already established themselves as an invasive species. The ants are originally from South America.

The researchers believe that queen red fire ants must have arrived in the port of Syracuse with other cargo and flown north to establish the nests. While individual red fire ants have been found on cargo at several European ports, they were never queens who established nests.

Ant stings in the Syracuse area have increased since 2019, meaning the ants might have arrived as much as four years earlier, the researchers noted.

While Sicily is an island, the researchers warn that the fire ants have the potential to one day establish themselves across much of southern Europe. An estimated 7% of the continent has a climate amenable to their subtropical tastes, including cities like Barcelona, Rome, London, and Paris.

Roger Vila, the study’s lead and the principal investigator at the Institute of Evolutionary Biology’s Butterfly Diversity and Evolution Lab, said that “Coordinated efforts for early detection and rapid response in the region are essential to successfully manage this new threat, before it spreads uncontrollably.”