Red fire ants are one of the world's worst and costliest invasive alien species - and they're making Italy their home.
One of the world’s worst invasive alien species has arrived in Europe for the first time, a new study reveals.
The red fire ant has formed a mature population in Sicily, Italy, according to research published in the scientific journal Current Biology.
The study warns that, with the help of global warming, the ants could spread across the continent. The climate in half of Europe’s urban areas is already suitable for the species.
This could have devastating and costly impacts on biodiversity, crops and human health.
Why are red fire ants dangerous?
As aggressive foragers, fire ants usually become the dominant ant species when they are introduced to a new territory.
This means they can devastate native ant populations and destroy native plants. They also have a venomous sting that can kill or injure frogs, lizards and small mammals.
The ants can also sting people making public areas such as parks unsafe for children. They may also cause a life-threatening allergic reaction in a small percentage of people who react to their venom.
Through predation, competition and stinging they have also been known to impact birds and fish.
As well as wreaking havoc on local ecosystems and biodiversity, fire ants can damage crops and infest electrical equipment.
They are the fifth costliest invasive species in the world, costing almost €20 billion in damage and management between 1970 and 2017, according to one estimate published in the journal Nature in 2021.
Fire ants are listed among the 100 worst invasive alien species by the Global Invasive Species Database.
Where do red fire ants come from?
Red fire ants - or Solenopsis invicta - originally come from South America.
In less than a century, they have spread via human trade throughout much of the United States, Mexico, the Caribbean, China, Taiwan and Australia. They often travel in infested soil, hay, mulch, and landscaping and construction materials.
Solenopsis invicta is already listed as a ‘species of concern’ on the EU’s invasive alien species list.
In the US alone, annual costs associated with the species are now estimated to be around $1 billion (€933 million).
New Zealand is the only country to have successfully eradicated this invasive ant.
Fire ants have previously been documented in products in Spain, Finland and the Netherlands but not in the wild as seen in Sicily, where 88 nests have been found.
Will fire ants spread across Europe?
Locals near the Sicilian city of Syracuse have been reporting frequent fire ant stings since 2019.
Genetic analysis of the ants found in the area suggests they may have originated in the southern US, mainland China or Taiwan.
It is unclear how or when the species was introduced to the area, but it may have been through the nearby Augusta cargo port.
Researchers found that the ants could establish themselves in 7 per cent of Europe and the Mediterranean under current environmental conditions. Agricultural areas are most at risk, while half of the urban areas studied have suitable conditions.
Of these, coastal Mediterranean cities with major seaport connections are most at risk.
Future projections show that Europe’s environment is likely to become more widely suited for the ants as the climate heats up.
The researchers advise that early detection and action are key in managing this new threat. Citizen reporting of stings and nests could help track the spread of the ants.