The research has confirmed the presence of the red fire ant, known as one of the world’s most invasive species and the fifth costliest to combat, in Europe. This discovery was made through a study published in the esteemed journal Current Biology, led by the Institute of Evolutionary Biology (IBE), a collaborative center of the Spanish National Research Council (CSIC) and Pompeu Fabra University (UPF). The study identified 88 red fire ant nests spread across 5 hectares near Syracuse, Sicily, Italy. These invasive colonies likely originated from China or the United States, both of which also suffer from this invasive species, as revealed by genetic analyses conducted in the study. The research was spearheaded by Roger Vila, a scientist at IBE, with Mattia Menchetti as the first author, an INPhINIT “la Caixa” pre-doctoral researcher at the same institution. Collaborators in this study included CREAF, the University of Parma, and the University of Catania.
The ecological models introduced in this study paint a grim picture of the red fire ant’s colonization potential in Europe, which could be further facilitated by climate change.
The red fire ant, scientifically known as Solenopsis invicta, hails from South America and has wreaked havoc on ecosystems, agriculture, and human health in numerous countries worldwide. Its sting is not only painful but also causes irritation, pustules, and allergic reactions, sometimes leading to anaphylactic shock. In less than a century, this ant has spread extensively in regions like the United States, Mexico, the Caribbean, China, Taiwan, and Australia. It has only been eradicated in New Zealand. In the United States alone, its presence results in an estimated annual loss of nearly six billion euros, while countries like Australia allocate millions for its eradication, with limited success.
Prior to this study, sporadic findings of S. invicta in imported products were recorded in Spain, Finland, and the Netherlands, but its establishment on the European continent had not been officially confirmed. Utilizing genetic analyses, the study concluded that the detected population probably originated in China or the United States, though the precise entry route remains unknown. The colonies were discovered in a suburban area of Syracuse, Sicily, which includes an estuary and a natural park. Given the isolated nature of this area, it is improbable that it served as the initial entry point onto the island. The research team determined that the entry point was likely a transit area with human activity, such as the commercial port of Syracuse. Wind direction analyses also suggested that some flying queen ants could have arrived from the northwest, where the port is located. As a result, the team recommends heightened monitoring for this invasive species in this vicinity.
According to distribution models developed in collaboration with CREAF, under current environmental conditions, this invasive species could potentially establish itself in roughly 7% of the European continent. The findings imply that approximately half of the urban areas in Europe possess a climate suitable for the red fire ant’s establishment. Major cities like Barcelona, Rome, London, and Paris could face significant disruption due to the ant’s abundance and aggressiveness. Mediterranean coastal cities, closely connected by seaports, are particularly vulnerable to S. invicta, which could further facilitate its spread. Factoring in climate change predictions, the situation may worsen as the species could potentially expand to other parts of Europe.
Roger Vila, the principal investigator at IBE’s group of Butterfly Diversity and Evolution and the study’s leader, emphasizes the importance of coordinated efforts for early detection and rapid response in the region to effectively manage this new threat before it becomes uncontrollable.
“The public could play a key role in the detection of S. invicta, considering that it is frequently found in urban and adjacent areas. It is possible to detect this ant due to its painful stings and the characteristic mounds of their nests, although confirmation by an expert is required,” adds Mattia Menchetti, an INPhINIT “la Caixa” pre-doctoral researcher at IBE and the study’s first author.
Given the red fire ant’s dispersal capabilities and the presumed existence of an unknown initial entry point, the research team recommends extending monitoring efforts to cover a larger geographical area. This study received support from the “la Caixa” Foundation and other organizations.
To read more about this research, refer to the article “The fire ant Solenopsis invicta is established in Europe” authored by Mattia Menchetti, Enrico Schifani, Antonio Alicata, Laura Cardador, Elisabetta Sbrega, Eric Toro-Delgado, and Roger Vila, published on September 11, 2023, in Current Biology, DOI: 10.1016/j.cub.2023.07.036.