These hornets are identified by their bright yellow legs, reaching about 25mm (approximately 1 inch) in length. For instance, an unchecked individual hornet colony is capable of “slaughtering” up to 90,000 pollinating insects within a single season.
Since the initial sighting of Vespa velutina —also known as the Asian or yellow-legged hornet—in the UK in 2016, beekeepers and scientists have been actively campaigning to mitigate the detrimental impact this invasive species could pose to Britain’s biodiversity and bee colonies.
Last year, an unusually wet spring and a disrupted summer seemed to have hindered the insect’s population growth, with the number of nests identified in the UK decreasing from 72 in 2023 to 24 in 2024. However, it was also the first year when the National Bee Unit confirmed via DNA analysis that the hornets had successfully reproduced and over-wintered in the UK.
Specialists are concerned that this year’s dry, sunny spring and the rapid expansion of the species in Europe will likely cause an increase in the hornet population.
“Exceptional” early sighting records of Asian hornets have been noted in Jersey, prompting experts to suspect that there could be record numbers attempting to establish nests in the UK this year.
“The initial queens were more than two weeks early this year,” stated John De Carteret, a founding member of the Jersey Asian Hornet Group, which currently has 550 traps in place this year. “We’re notably concerned.”
In Jersey, as of April 11, there have been 262 queen Asian hornets recorded, marking a year-on-year increase of 1,090%.
“Once we arrive at 266 queens, it will match the total from last year, which figure wasn’t achieved until June 25,” De Carteret indicated.
Ian Campbell of the British Beekeepers Association commented, “There’s a strong likelihood that this year’s numbers will be at least on par with 2023 and potentially even higher. It wouldn’t be surprising if counts exceeded those of 2024.”
The species is carnivorous, and a typical nest, comprising between 2,000 and 3,000 Asian hornets, can consume over 11kg (approximately 24lb) of insects per season according to Campbell—equivalent to the weight of 90,000 bees.
The public is urged to “remain vigilant everywhere” and learn to identify and report Asian hornets, which are distinguished by their yellow legs and a clear orange band on the fourth segment of their abdomens, along with the velvety-black thoraxes that set them apart from the native European hornet.
Possible sightings of concern should be reported to the government’s National Bee Unit through the Asian Hornet Watch app or online, using the UK Centre for Ecology and Hydrology (UKCEH) reporting tool.
Kate Wilson, the head of the National Bee Unit, stated, “Yellow-legged hornets significantly harm native pollinators, including our cherished honeybees. Thanks to increasing reports through 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.”
These sightings assist efforts aimed at controlling the spread of Asian hornets. “I collected one from an 80-year-old lady who caught it in a yogurt tub, while the youngest person to report one was eight,” De Carteret mentioned.
Ecology professor Helen Roy from UKCEH and Exeter University posits that the hornets represent “a major threat” to wildlife and biodiversity: “There isn’t a natural predator known that can control the Asian hornet.”
It is believed that successive generations stemming from a single mated queen—which was inadvertently introduced to France in a container of Chinese crockery in 2004—have now reached 15 European countries, including the UK. “In some countries like Spain and Belgium, we’ve seen numbers rise from a handful of nests to 10,000 nests in four years,” Campbell stated.
France is believed to host over half a million nests, with researchers estimating this could be costing the French economy about €30.8m annually in lost bee colonies and honey revenue while the invaders have decreased honey production by 35% in Portugal and 50% in Liguria, Italy, in recent years.
In March, Exeter University researchers published the first large-scale study of the Asian hornet’s diet, finding 1,400 different species in their guts. Of the top 50 invertebrate prey species identified, 43 were known to visit flowers. These included Europe’s principal crop pollinators: the European honeybee, the buff-tailed bumblebee, and the red-tailed bumblebee.
De Carteret, a retired police forensic officer, remarked that hornets typically “slaughter” this prey by severing their heads, wings, legs, and abdomens, allowing their thorax, a protein source, to be fed to the queen’s larvae.
Thus far this year, there have been only two confirmed sightings of yellow-legged hornets in the UK, but now is the time for vigilance, Roy said.
Had the government not razed the nests that the public reported since 2016, modelling from Exeter University suggests that the hornets would already be established in vast areas of England and Wales, with incursions into Scotland.
Campbell underlined the importance of attempting to photograph any suspected Asian hornets and their nests: last year, only about 70 out of more than 29,000 reports were deemed accurate enough for confirmation. “Successful eradication demands that the National Bee Unit locate every single nest,” he noted.
New hornet queens are ceaselessly arriving in the UK from Europe to replace those that have been removed. “The Asian hornet can arrive in a variety of ways. It may come in fresh produce or inside a car, making any Channel crossing an entry point,” Roy affirmed. “Everyone needs to remain watchful, everywhere.”
