Asian hornets found in East Sussex, UK, this spring are genetically linked to a nest destroyed in the area last year, confirming that the invasive species has overwintered in Britain for the first time.
UK officials have been fighting to prevent the Asian hornet (Vespa velutina) from becoming established in the country since the first sighting in 2016.
Asian hornets are smaller than native European hornets (Vespa crabro), and pose no greater risk to human health. But their voracious appetites and predatory hunting behaviour are a threat to the UK鈥檚 honeybee colonies and native bee populations.
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The species first appeared in Europe in 2004, when they were spotted in France. Its numbers have grown quickly on the continent, but it has so far been kept at bay in the UK due to a policy of eradication by the National Bee Unit (NBU), an arm of the government-run Animal and Plant Health Agency. This involves encouraging the public to report any possible sightings, killing every hornet found and destroying every nest.
But the NBU may be losing the fight to stop the species settling. DNA testing conducted by the NBU shows three queen hornets caught at Four Oaks in East Sussex are the offspring of a nest destroyed in Rye, East Sussex, in November 2023.
鈥淔inding hornet queens this spring related to a nest last year is an announcement we really weren鈥檛 hoping to happen, because it is the start of establishment,鈥� says Ian at the British Beekeepers Association.
Data already suggests 2024 will be a record year for Asian hornet activity. There have been of Asian hornets in 2024 so far and one nest destroyed in Kent. By the same date in 2023, just three sightings had been confirmed.
Last year was a record year for Asian hornets, with 56 sightings confirmed and 72 nests destroyed. Most of the hornets are found in south-east England, with Kent, East Sussex, Devon and North Yorkshire being particular hotspots. It is thought most specimens hitch a lift on cargo trucks, ferries and cars crossing the English Channel.
But the NBU says there is still not enough evidence to show that Asian hornets are now established in the UK. For that to be the case, it said there should be evidence of a reproducing population present in the wild 鈥渇or a significant number of generations鈥�. 鈥淭he presence of overwintered hornets produced from a nest found and destroyed late last year is not considered to be strong evidence of an established population,鈥� it said in a statement.
Nevertheless, the growing numbers of sightings are a huge concern for beekeepers. Asian hornets are known to 鈥渉awk鈥� outside bee hives, preying on bees as they fly in and out of their hives. A single Asian hornet nest can contain up to 3000 hornets and can consume 11.3 kilograms of insects over a single summer. Each nest can produce 180 to 500 new queens.
Honeybee hives are 鈥渓ike an all-you-can-eat buffet鈥� for Asian hornets, says Campbell. 鈥淭he evidence from France is that [beekeepers] are losing 30 per cent of their colonies. In some areas it is way higher than that.鈥�
The spread of Asian hornets across the UK could have wider ecological implications, says at University College London, given they have no natural predators. 鈥淭he problem is that any invasive species out of its native zone is likely, or has the potential to, cause ecological imbalance,鈥� she says.
But she stresses the importance of the public correctly identifying Asian hornets, which have distinctive yellow leg ends. Native European hornets, which look similar, are important to protect. 鈥淲asps in their native habitat are really important pest controllers, pollinators and decomposers,鈥� she says.
