The study confirms that fire ants, considered one of the world's most invasive species and the fifth most expensive to control, have been introduced and established in Europe. A study led by the Institute of Evolutionary Biology (IBE), a joint center of the Spanish National Research Council (CSIC) and the University of Pompeu Fabra (UPF), published in the prestigious journal Current Biology, discovered 88 fire ant nests near the city of Siracusa, Sicily, Italy, covering an area of 5 hectares.
The invasive fire ant has established itself in Europe, with colonies found in Sicily, Italy. This invasive species, which poses a threat to ecology and health, has the potential to colonize 7% of Europe. The researchers stressed that rapid response and widespread surveillance are urgent. Photo credit: Jesse Rolabaugh
According to the study's genetic analysis, these fire ant colonies may have come from China or the United States, which are themselves countries invaded by fire ants. The work was led by Roger Vila, a scientist at the International Bureau of Education, and led by Mattia Menchetti, a pre-doctoral researcher at INPhINIT "la Caixa" at the institute, as first author. CREAF, the University of Parma and the University of Catania also participated in the work.
Ecological modeling introduced in the study makes worrying predictions about the ant's potential to colonize Europe, which could be facilitated by climate change.
Fire ants (Solenopsis invicta) are an invasive species from South America that have caused significant impacts on ecosystems, agriculture, and human health in many countries around the world. Its sting is painful and irritating and can cause pustules and allergic reactions, leading to anaphylactic shock in severe cases.
In less than a century, the ants have spread across much of the United States, Mexico, the Caribbean, China, Taiwan and Australia, with only New Zealand eradicating them. It is estimated that the presence of red imported fire ants in the United States causes losses of nearly 6 billion euros each year, while countries such as Australia have invested millions of dollars in eradicating red imported fire ants, but with little success.
Prior to this study, RIFA had been occasionally found in imported products from Spain, Finland and the Netherlands, but their presence in continental Europe had never been confirmed.
Through genetic analysis, the study concluded that the detected population likely originated in China or the United States, but the route of entry was unclear. The breeding colony is located on the outskirts of the city of Siracusa in Sicily and consists of an estuary and a natural park. The area is isolated and therefore unlikely to be the first stop on the island. The team concluded that the entry point must have been a transit area with human activity, such as the commercial port of the city of Syracuse. In fact, analysis of wind directions suggested that some flying ant queens may have arrived from the northwest, where the port of Syracuse is located, prompting the team to recommend monitoring for the invasive species.
Using a distribution model developed in partnership with CREAF, the study concluded that under current environmental conditions, the invasive species has the potential to establish itself in approximately 7% of the continent.
The findings show that half of Europe's urban areas have climate conditions suitable for the survival of this invasive species. Large cities such as Barcelona, Rome, London or Paris may be severely affected by this invasive species, which may affect people's lifestyles due to their abundance and aggressive nature.
Mediterranean coastal cities are closely connected to seaports and are best suited for the growth of S.invicta, which may facilitate its spread. Given climate change projections, the situation is likely to get worse as the species threatens to expand into other parts of Europe.
"To successfully control this new threat before it spreads out of control, early detection and rapid response coordination in the region are crucial," warned Roger Vila, lead researcher in the IBE's Butterfly Diversity and Evolution Group.
"Given that this ant is often found in cities and neighboring areas, the public can play a key role in discovering this ant. Although it requires expert confirmation, it is possible that the stinging sensation of this ant and the characteristic mounds of its nests can be detected," explains Mattia Menchetti, a pre-doctoral fellow at INPhINIT "la Caixa" at the International Bureau of Education and first author of the study.
Given the spread ability of this invasive species and the presence of unknown initial entry points, the team recommends expanding monitoring to a larger geographic area.