Asian or yellow-legged hornets (Vespa velutina), a highly invasive species, pose a serious threat to the UK’s biodiversity, especially pollinators.
These hornets are around 25mm (nearly 1 inch) long and are easily identifiable by their bright yellow legs, black velvety thoraxes, and a distinctive orange band on the fourth segment of their abdomens.
A single colony of these predators can kill up to 90,000 pollinating insects in one season, making them a major concern for conservationists and beekeepers alike.
First detected in the UK in 2016, Asian hornets have triggered an urgent and ongoing response from scientists and beekeeping groups. In 2023, 72 nests were recorded, but in 2024 that number dropped to 24—partly due to poor weather conditions. However, experts are warning that the dry, sunny start to 2025 may reverse this trend.
Notably, 2023 marked the first confirmed instance of the species successfully breeding and overwintering in the UK, verified through DNA analysis by the National Bee Unit.
The hornets have spread rapidly across Europe since they were accidentally introduced to France in 2004, reportedly via a shipment of Chinese pottery. One mated queen’s descendants now populate 15 European countries.
“Unprecedented” early sightings of Asian hornets have been recorded in Jersey, leading experts to suspect that record numbers could try to establish nests in the UK this year.
“The first queens were more than two weeks early this year,” said John De Carteret, a founding member of the Jersey Asian Hornet Group, which has about 550 traps in place this year. “We’re obviously concerned.”
In Jersey alone, 262 queens were found by 11 April this year—a staggering 1,090% increase compared to the same period in 2024.
“When we reach 266 queens, we will equal the total from 2024 – and that figure wasn’t reached until 25 June,” said De Carteret.
Ian Campbell, of the British Beekeepers Association, said: “There’s a strong risk of this year’s numbers being at least as high as in 2023 and the potential to be even higher. It would be a surprise if numbers were not above the 2024 level.”
France now has more than half a million nests, while countries like Spain and Belgium have seen nest counts grow from a few to 10,000 in just four years.
“In some countries like Spain and Belgium, we’ve seen numbers increase from a handful of nests to 10,000 nests in four years,” said Campbell.
These hornets are highly carnivorous. A typical nest of 2,000–3,000 hornets can consume over 11kg (24 pounds) of insects each season, much of that being pollinators such as bees.
A large-scale study from Exeter University in March identified 1,400 species in hornet digestive systems. Alarmingly, 43 of the top 50 prey species were flower-visiting insects, including the European honeybee, buff-tailed bumblebee, and red-tailed bumblebee—Europe’s primary crop pollinators.
Hornets kill their prey by tearing off the heads, wings, legs, and abdomens, feeding only the thoraxes—rich in protein—to larvae. The ecological damage is already being felt: honey production has dropped by 35% in Portugal, and 50% in Liguria, Italy. France estimates it could be costing the French economy an annual economic impact of €30.8 million due to lost bee colonies and honey production.
Despite only two confirmed sightings of yellow-legged hornets in the UK so far this year, experts stress the need for public vigilance.
The government urges citizens to learn how to recognise and report the species. Sightings should be submitted through the Asian Hornet Watch app or via the UK Centre for Ecology and Hydrology’s (UKCEH) online reporting tool. Photographs of hornets or their nests are especially valuable for verification.
“Yellow-legged hornets cause significant damage to native pollinators, including our much-loved honeybees,” said Kate Wilson, head of the National Bee Unit. “Thanks to increasing reports to the app and online, it is not unexpected that sightings may occur earlier in the year. We encourage the public to remain vigilant and continue to report any potential sightings to us.”
Such sightings can help us to understand the national picture.
“I collected one from a lady in her 80s after she captured it in a yogurt tub, while the youngest person who reported one was eight,” De Carteret said.
Professor Helen Roy, an ecologist with UKCEH and the University of Exeter, warns that the species presents “a major threat to wildlife and biodiversity.”
“There isn’t a natural enemy that we’re aware of that could control the Asian hornet.”
Without intervention, modelling by Exeter University suggests these hornets could have already been widely established in England and Wales and entering Scotland.
Although the UK has managed to contain the spread so far, experts like Campbell emphasise that this success hinges on rapid nest destruction and accurate public reporting. In 2024, out of over 29,000 public reports, only 70 were confirmed sightings.
“To be successful with eradication, the National Bee Unit needs to get every single nest,” he said.
Meanwhile, new hornet queens continue to arrive from Europe, replacing those eradicated. The message from scientists is clear: with spring underway, now is the time to stay alert.
“The Asian hornet can arrive in a lot of different ways. It can come in on fresh produce or within someone’s car, across any Channel crossing,” Roy said. “Everyone needs to be vigilant, everywhere.”
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