It is likely the Asian hornet has become established in the UK, conservationists fear, as a record number of nests have been found.
There has been a sharp rise in sightings of the invasive species in the UK this year; the previous two years only had two sightings each, whereas there have been 22 confirmed so far in 2023. In total there have been 45 sightings since 2016.
The vast majority of the sightings have been in Kent and some experts are concerned the species may have established itself there. The government’s strategy is to locate and kill every hornet and destroy all nests to prevent them from staying over winter and multiplying. Once they are established, it is almost impossible to get rid of them.
The bumblebee conservation expert Dave Goulson, a professor of biology at the University of Sussex, said he feared it was likely the hornets had become established in Kent.
He told the Guardian: “It is a bit too early to say for sure but the situation looks ominous, with a record nine nests found and destroyed this year so far. If even one nest evades detection and reproduces it will then probably become impossible to prevent them establishing.”
Goulson said they would likely remain for good once established. “I think it is inevitable that they will eventually establish in the UK, and once here it is hard to see how they could be eliminated.”
This would be terrible news for native bees, which the hornets dismember and eat. They have thrived in France, where they have caused concern with the number of insects they have killed. They sit outside honeybee hives and capture bees as they enter and exit. They chop up the smaller insects and feed their thoraxes to their young.
Goulson added: “The arrival of Asian hornets would provide a significant new threat to insect populations that are already much reduced due to the many other pressures they face, such as habitat loss, pesticide use and so on.”
Matt Shardlow, the chief executive of the insect charity Buglife, agreed with Goulson, saying: “With four new Asian hornet nests being detected in the last week and a strong cluster in coastal Kent it seems likely that the species has colonised England. The Asian hornet is a risk to biodiversity; in particular it can hunt large numbers of wild solitary bee species.
“It is too early to give up on control efforts. Removing nests has probably managed to slow its colonisation, and the abundance of different wasps can be strongly influenced by weather, so we can still hope that eradication efforts, perhaps with some lucky weather, might nip this colonisation in the bud.”
The British Beekeepers Association trustee Julie Coleman, who lives in Kent, said hornets could have already overwintered in the area. “The fact that we seem to have a cluster around the coast in Kent, also Dorset, Plymouth, Weymouth and Hampshire, makes me think they are coming across on the wind. And there could have been an overwintered nest in Kent which has sent out hibernating queens in the autumn.”
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Asian hornets first came to Europe in 2004 when they were spotted in France, and it is thought they were accidentally transported in cargo from Asia. They rapidly spread across western Europe and have crossed the Channel to Britain, probably also in cargo, but they can also come on the wind or under their own steam.
Experts recently warned that lax post-Brexit trade rules could be helping the hornets colonise Britain. The EU has banned the import of soil in pot plants from the UK since Brexit, partly because invasive species such as the Asian hornet can travel undetected in soil. The UK has not put reciprocal bans in place, however, meaning damaging species from the continent could be transported in soil.
Asian hornets are smaller than native hornets and can be identified by their orange faces, yellow-tipped legs and darker abdomens.
Nicola Spence, the chief plant and bee health officer at the Department for Environment, Food and Rural Affairs, said: “Evidence from previous years suggested that all 13 Asian hornet nests found in the UK between 2016 and 2022 were separate incursions and there is nothing to suggest that Asian hornets are established in the UK. We have not seen any evidence which demonstrates that Asian hornets discovered in Kent this year were produced by queens that overwintered. We plan to do further detailed analysis over winter to assess this.”