Ant plague in Germany? Experts warn of invasive species Tapinoma magnum

Kehl. The remains of the climbing frame protrude from the ground like the skeleton of an excavated prehistoric animal. It's a relic from a bygone era. Where there once was a playground, there is now only a large expanse of sand. Two excavators flank the frame, as if trying to make it clear who their next victim will be.

The cause of the dreariness on the playground in Kehl, southwest Germany, is only a few millimeters in size – and is driving cities and municipalities to despair: the Tapinoma magnum, the large gland ant. This invasive species, originally native to the Mediterranean, is now feeling quite at home in Germany – not least due to climate change. And it seems that sooner or later, wherever it has settled, excavators will have to move in and demolish everything.

Last year, millions of Tapinoma magnum ants crawled into cars, dishwashers, and children's rooms in Kehl. They chewed through electrical cables and brought down the internet. The playground was also closed because the tiles were lifting and hollows were forming—the safety risk to the children was too great. The case made national news. Reports have dwindled, but the ants haven't disappeared.

Where there once was a playground, there is now only sand. The reason: the invasive ant species Tapinoma magnum.

Source: Josephine Kanefend

The destructive power of Tapinoma magnum lies in its ability to form supercolonies: Instead of fighting among themselves like other ant species, different colonies join forces. This allows them to produce hundreds or even thousands of queens – and reproduce rapidly. Such a supercolony can cover up to 20 hectares.

This also makes it so difficult to control the ants. Conventional insecticides are of little use. Only the widespread use of hot water seems to have an effect so far. Last year, the city of Kehl purchased a special device for this purpose and created two full-time positions just for the control of Tapinoma magnum – costs in the six-figure range. This helps somewhat. However, it hasn't yet been able to get rid of the ants sustainably.

And the large gland ant is no longer just a problem for Kehl – ​​it's spreading throughout Baden-Württemberg, and a sighting has even been reported in Hamburg. In Hanover, Tapinoma ibericum, a close relative of Tapinoma magnum, is causing problems at a supermarket . So, is a Germany-wide ant plague looming?

A hundred kilometers from Kehl, Amelie Höcherl is leaning over her "Bino," as she affectionately calls it. Höcherl is an entomologist at the Stuttgart Natural History Museum. Since January, she has been working on a new research project, a collaboration between the Stuttgart museum and the Karlsruhe Natural History Museum.

The aim: “Genomic and ecological analyses of the spread of the invasive ant species Tapinoma magnum in Baden-Württemberg as a basis for effective management.”

Höcherl and her colleagues want to find out how the Tapinoma magnum is spreading and what this means for future management, because: "The ant is here to stay. We can't get rid of it. This is now more a question of management," says Höcherl. In other words: Yes, it's likely that the large gland ant will soon be on the doorstep of other cities – if it isn't already there.

The Tapinoma magnum is pitch black and can form supercolonies that sometimes spread over several hectares.

Source: Uli Deck/dpa

To find out, the researchers rely on the public's help. Anyone who suspects Tapinoma magnum can submit photos or samples of the insects. This research approach, which involves citizens in scientific research, is called citizen science. The submitted material is then examined by the researchers. If they confirm the suspicion, Tapinoma magnum has crawled a little further on the map of Germany.

"It's actually a miracle that there are massive outbreaks in southwest Germany, but no reports yet from Thuringia or Saxony," says Dr. Bernhard Seifert, an ant expert at the Senckenberg Museum of Natural History in Görlitz.

But that's not because there are no large gland ants in the east – it's much more likely that they haven't been discovered yet. He has already alerted the Saxon State Office for the Environment to the impending danger, but so far nothing has happened. "They're asleep," says Seifert.

This is an accusation that doesn't just come from the scientific community. "At first, it was downplayed," says Herbert Michalski. His house is right next to the ant-infested playground in Kehl. He says, "All this mess started here before the coronavirus pandemic." But the city didn't react quickly enough.

In Kehl, Tapinoma magnum is now being controlled with hot water, as conventional insecticides are of little help.

Source: Annette Lipowsky/City of Kehl/dpa

Every morning, Michalski now patrols the area – “so that the bastards don’t come too close to me.” His wife wants to skip their summer vacation this year for fear that the ants might invade the house.

At least in Baden-Württemberg, politics has woken up – thanks in part to Bernd Mettenleiter. He drives up to the Kehl playground in his electric car on this Monday afternoon. Striped shirt, blue jeans, sneakers – a textbook Green Party politician.

Mettenleiter is a member of the Baden-Württemberg state parliament for the Kehl constituency. He initiated the Tapinoma research project. It is initially planned for two years. Mettenleiter was able to secure €210,000 from the state budget for it.

The former biology teacher has no reservations about ants—quite the opposite. Mettenleiter kneels on the sand, grabs an insect, and crushes it between his thumb and index finger: "Take a sniff. It smells like nail polish remover." That's a matter of personal taste, but the characteristic smell is definitely a feature of Tapinoma magnum.

"The ant plague is obviously a financial challenge for municipalities," says Mettenleiter. Therefore, it is important to find "future-oriented solutions." The research project aims to help with this.

Bernd Mettenleiter (Green Party) initiated the new Tapinoma research project, allocating €210,000 from the state budget of Baden-Württemberg.

Source: Josephine Kanefend

The idea is for those affected and municipalities to network and exchange knowledge. After all, Kehl isn't the only city experiencing problems with Tapinoma magnum. Contact is also being maintained with partners in France and Switzerland.

The fact that the ant doesn't cause problems in its native regions is due to its natural enemies there. In Germany, however, Tapinoma magnum appears to be causing little disruption. It was probably introduced via plant transport from the Mediterranean region. The first cases were recorded in Rhineland-Palatinate in 2009.

Since then, the ant has continued to spread. Because its nests are located up to one meter underground, it survives even in winter – even at temperatures as low as minus 15 degrees Celsius. Climate change is also likely favoring the spread of Tapinoma magnum.

"Our hypothesis is that climate change plays a role," says Amelie Höcherl from the Stuttgart Natural History Museum. Finding out is one goal of the new research project. To do so, the scientists are comparing the distribution of Tapinoma magnum with climate data. This will enable them to make predictions for the future.

Increased temperatures and less frost in Northern Europe mean that invasive species from warmer regions can survive here in the long term. Therefore, the Tapinoma research project could also provide important insights for dealing with other non-native species, says Höcherl.

Höcherl speaks a lot in the subjunctive, speaks of "hypotheses" and still-open "research questions," and repeatedly clarifies her own statements so as not to create a false impression. Many things remain unresolved, some will probably never be resolved. That's just how science works.

Some people seem unable or unwilling to understand this. Too slow, too vague, too contradictory—accusations that scientists are repeatedly confronted with. And then there's the infamous ivory tower.

Amelie Höcherl and her colleagues are studying Tapinoma magnum to find out more about the spread of the ant and how to deal with it in the future.

Source: Josephine Kanefend

That's why Höcherl is a firm believer in citizen science: "The advantage is that citizens can participate in science." Furthermore, without citizen scientists, researchers would have significantly fewer ant samples. "Many eyes see more," says Höcherl.

Green Party politician Mettenleiter is also enthusiastic about citizen science. His inner teacher briefly shines through: "Behind it all lies the secret plan to show people that science isn't aloof and operates from an ivory tower, but creates concrete solutions."

This curriculum doesn't seem to have sunk in yet. The Osthofs' doorbell rings. The house is across the street from the Michalskis, who aren't going on vacation this year because of the ants. An older gentleman wearing sweatpants and slippers opens the door.

Had he heard about the new research project? "No." And: "It doesn't make any difference at the moment. A dissertation will emerge from it at some point, but we need solutions now, not sometime in the future."

He himself plans to buy a certain ant-fighting gel next, something he read about online. His neighbor, on the other hand, swears by baking soda. She's not entirely convinced by the city's hot water treatment: "The ants will laugh their heads off. They should do something proper." She lets the city maintenance workers onto her property anyway. It can't hurt, after all. At least, no more than the ants.