It may seem like an annoying insect, but it is not. The red fire ant (Solenopsis invited) is considered one of the worst invasive species in the world and the fifth most difficult to combat. And it has arrived in Europe, after colonizing half the world. A group of scientists found 88 nests spread over five hectares near Syracuse, Sicily (Italy), in what is considered the first official sighting. The species, native to South America, has a major impact on ecosystems, agriculture and human health. As its name suggests, the bite is painful, irritating and produces pustules and allergic reactions, in addition to causing anaphylactic shock. The models developed by the study, led by the Institute of Evolutionary Biology-CSIC, show alarming predictions about the colonization of this ant in Europe, which could be favored by climate change.
These unwanted colonizers may come from China or the United States, where it is also an invasive species, concluded the work, published in the scientific journal Current Biology. In Spain, Finland and Holland some specimens have been found in imported products, but there is no confirmation of colonies anywhere in Europe. Once here, the situation is worrying. “The big problem is stopping them and the chances of success are small,” said Roger Vila, principal investigator at the Institute of Evolutionary Biology. “If there’s any option, it’s now, before they start expanding, then it’s impossible,” he said. When an invasive species lands somewhere in the world, a period of latency occurs, which then transitions to exponential growth.
Under current climate conditions, the fire ant can establish itself in 7% of Europe, researchers have shown. Half of the urban areas of the continent would be suitable for its construction and, due to its abundance and aggressiveness, it could change the lifestyle of people in big cities like Barcelona,​​​​ Rome, London or Paris.
The first sign that something was happening in Syracuse came from information from people who suffered from painful stings at a marina. “They sent us photos and we saw that it was the ant,” said Vila. To prove this, part of the team – made up of Spanish and Italian researchers – traveled to the area and confirmed through DNA sequencing that it was the dreaded ant. “When we talked to people we found out that they had been suffering from bites for three years,” he said. This fact made them afraid to have more colonies.
It is very difficult to know the path through which invasive species arrive. On this occasion, the exact point is also unknown, but by studying the wind direction, researchers suspect that some flying queen ants may come from the northwest, where the commercial port is located. in Syracuse, about 14 kilometers from the pier where the bites occurred. The common thing is that the entrance is places with human activity and commerce from other countries, such as the pier, which has more commercial activity than the small port where the nests are located. The great connection that exists between the cities of the Mediterranean coast favors this expansion.
Many queens in a nest
The researchers advise the regional Executive to create an elimination plan, which must be approved by the Government of the country. This is not easy because of the fire ant’s ability to multiply. “First we have to eliminate what we found, and to do this we have to kill the queens with poison bait that the workers bring to the nest,” explained Vila. They are enormous colonies, stretching underground with tens of thousands of ants and dozens of queens. “We get a variety that creates super colonies, some that only have one queen per nest,” he said. The second step is to monitor, look for other sources of invasion in nearby areas, especially in the direction of the commercial port of Syracuse.
The speed of its expansion is evident. In less than a century, the species has established itself in most of the United States, Mexico, the Caribbean, China, Taiwan and Australia, and has only been eliminated in New Zealand, the authors show in a statement. In the United States, its presence causes an estimated loss of around six billion euros per year. And in Australia they have dedicated millions to eradicating it, which has not succeeded so far. Invasive species cause annual costs to the world of 423 billion dollars (about 393 billion euros), increasing economic losses and efforts to eradicate them. And they are one of the five main causes of the crisis of loss of biodiversity that plagues the planet, concludes the Report ‘Assessment of invasive exotic species and their control’, presented on Monday.
Mattia Menchetti, one of the scientists of the study, explained that the species “reduces the biodiversity of invertebrates and small vertebrates, and can even cause damage and kill young individuals of large animals.” They also cause damage to agriculture by eating parts of plants and even infrastructure with damaged wiring.
