Anyone with ants in garden told 'watch out' for invasive 'dangerous' species spotted in UK

Gardeners have been asked to watch out for a new destructive species of ant which has been spotted in the UK. The Tapinoma magnum ant is thought to have arrived in Europe through imported plants at garden centres.

And they have caused mayhem - and it has been described as one of Germany's most destructive invasive species.

But they've been spotted in the UK now, and there are signs that the ants are anything other than normal, according to some experts.

The tiny species, measuring barely 4mm, was once confined largely to the warmer climates of the Mediterranean area. It has been found to have settled early on in Italy, either naturally or through the flourishing trade between Ancient Rome and northern Africa. Lately, it has been settling in Germany's southwest and Rhineland areas.

And now it has been found in the UK - including in Royston, Hertfordshire. The ants are vicious and have been known to bit through all sorts of infrastructure. In Kehl, near the French border, the city reported damage to public infrastructure, and cuts to power and the internet, caused by the ants.

The ants have also been found in ten European countries, including France, Belgium, the UK and even Azerbaijan.

The ants penetrate cavities in buildings and infiltrate electrical boxes, using cables to move into the spaces, which caused the power cuts in Kehl. In Karlsruhe, the city's suburban railway is struggling with loose pavements near the platforms, undermined by ant colonies.

The British Pest Control Association this week highlighted the issue and Niall Gallagher, BPCA Technical Manager, said: "Research shows that T. magnum colonies are remarkably cold-tolerant for a Mediterranean species. In Germany, for example, they've survived two-week frost periods with average temperatures of -6.6°C and minimums down to -15°C without issue.

"This kind of hardiness, combined with warmer winters and longer summers in the UK, potentially makes colonisation more likely over time."

Niall said they have behaviours which show what they are -including how they form long trails over patios, "In truth, most people - and even professional pest controllers - would struggle to tell Tapinoma magnum apart from common species like the black garden ant (Lasius niger).

"Visually, the two ants are very similar, and the subtle anatomical differences require lab analysis to confirm. Unless you're a specialist with experience in ant taxonomy, identifying T. magnum based on appearance alone is difficult.

"In the field, you'd probably rely on behavioural clues - particularly their distinctive procession behaviour. These ants often form long, busy trails across patios, pavements and walls, connecting different parts of their supercolony."

Wildlife website Bees, Wasps and Ants said a member had found the species in Royston Herts. In a new post it said: "They seem to be thriving and have several nests with many queens in a private garden and have also been seen in two other gardens with one being 200m away. The resident, a professional gardener, recognised some very small black ants in his garden as something special about 5 years ago. It was only when he posted some photos and notes on the UK Bees, Wasps and Ants Facebook page that interest was piqued.

"Samples were requested and some sent to Bernhard Seifert in Germany who kindly identified them as T. pygmaeum. These ants are native to southern Europe and their presence here is likely a consequence of global warming. However as they have been thriving outdoors in Royston for 5 years or more it seems very likely that they could turn up elsewhere in Britain so please keep an eye out for them.

In Marlen, a suburb of Kehl, a children's playground had to be closed after the ground began to buckle under the sheer number of ants tunnelling beneath it. There is also a psychological cost as the animals settle in private gardens, where they leave bite marks on their hosts' limbs, invade their homes and lead to a proliferation of plant lice, whose manure serves as nutrition for the ants.

Manfred Verhaagh, one of the scientists behind a Tapinoma research project at the Natural History Museums of Karlsruhe and Stuttgart has spent "hours" researching a way to defeat them. "I've found almost nothing," he said, adding that aggressive pesticides are often forbidden in Germany and may fuel the growing decline in all insects.

Municipal teams in cities such asTübingen and Kehl now deploy boiling water at 95°C into the soil to avoid chemicals. But Tapinoma magnum is also known to be able to weather extreme temperatures by retreating further into the ground, where it can survive temperatures below minus 10C.