I’m an Asian hornet specialist
Asian hornet numbers are expected to reach new record levels in the UK this summer – but there are ways to avoid getting a nasty sting.
Nature groups have issued a warning of a potential surge this summer not only from hornets flying over the Channel from Europe but also as a result of nests established in 2023.
There were already a record 56 sightings and 72 nests across the UK last year, mostly in Kent and the south of England.
So far, the Department for the Environment, Food and Rural Affairs has recorded eight confirmed sightings so far this year.
But experts believe the number of nests could exceed 100 this year.
Ian Campbell, from the British Beekeepers’ Association, said Asian hornets are not “individually aggressive” but the danger is if you get anywhere near a nest.
Parents should tell children to avoid going near to bees nests to avoid stings.
“They defend their nests aggressively,” Mr Campbell said. “They don’t swarm but they will come out in high numbers and attack whoever is too close to the nest.”
This can often be a problem for agricultural workers but they also pose a threat to biodiversity as their preferred diet is honey bees and insect pollinators, he said.
Paul Hetherington, spokesperson for the conservation charity Buglife, also said the hornets are not a risk to humans unless you are allergic to their sting, but that they do pose “significant risks to our native populations of bees”.
“One nest of Asian hornets is probably capable of taking out a bee colony in a day,” he said. “One hornet can eat 50 honey bees in a day.”
Mr Hetherington said an Asian hornet’s sting is similar to a wasp and the key to not being stung was to leave them alone.
“Number one: don’t poke around in anything that has wasp or bees or hornets in it. They are not especially aggressive.
“It’s only if you disturb a nest you could get stung by them.”
They tend to be found “lurking outside a hive” and should be reported straight away so they can be traced back to their nest, he added.
“We have hand a handful [of Asian hornets] in previous years but last year was a really big increase,” Mr Campbell said. “The big concern is that they have been spreading in Europe after arriving in France in 2004. There are now significant numbers in Northern France, Belgium and the Netherlands.
“They are really quite close to us and they are getting across the Channel.”
There has been some “evidence of relatedness” among nests found this year in East Sussex with nests found last year, which suggest the Asian hornets have reproduced.
“That’s a moment we didn’t really want because that indicates the start of them being established in the UK,” he added.
A queen hornet tends to start a small nest in spring, then build a bigger secondary nest around July which can have around 3,000 hornets.
In October, each nest will produce around 300-plus gynes (potential queens) and mating males. Only a small number of these queens will successfully mate and survive the winter but those that do will establish a new nest next spring.
Mr Campbell said there is “a potential for a year on year increase” as has happened in Spain and Belgium previously, once the species has become established.
“They went from finding a handful of them a year to finding 10,000 nests a year,” he said. “We are concerned it will be worse in the UK this year.”
It is difficult to predict numbers, he said, as growth wasn’t in a linear fashion but “overall we are worried the trend could be to increase significantly”.
Asian hornets are about 25mm long and are slightly smaller than the native European hornet but twice the size of a bee, with yellow lower legs and a yellow/orange stripe on their rear abdomen.
Their nests are usually about 60cm across but they can be bigger than that.
Mr Campbell encouraged anyone who thinks they spot one to report them using the Asian Hornet Watch App and the National Bee Unit will investigate.
“We are still in the eradication phase and that’s what we hope will work,” he said, “but wee have to be prepared for circumstances which mean we could be overwhelmed in time.”
Mr Hetherington said the Asian hornet arrived in the South of France in packing cases which came from China, probably in sawdust. “It is very likely we are going to see more and more Asian hornets in the UK.
“They are capable of flying distance of crossing the channel. We know they have already flown the Channel last year, they are going to keep arriving by flying the Channel.”
He said more than 14 nests in Kent were not discovered until September or later last year, which means the new queens will have had time to flee the nests.
“It means there could be 140 potential nests started this year. I think we are likely to have well over 100 nests this year.”
He said the spread of Asian hornets was “more about global trade and stuff not being monitored” rather than climate as they come from the mountains of Nepal and need temperatures to drop below 5°C in the winter to prompt them to hibernate.
Nicola Spence, the UK’s chief plant health officer, is urging UK beekeepers and the public to be increasingly vigilant to the presence of Asian hornet and report any sightings as we move into the peak summer season. She said: “By ensuring we are alerted to possible sightings as early as possible, the public can help us take swift and effective action to stamp out the threat posed by Asian hornets.
“While the Asian hornet poses no greater risk to human health than other wasps or hornets, they can damage honey bee colonies and harm other pollinators.”
If you suspect you have seen an Asian hornet you should report this using the iPhone and Android app “Asian Hornet Watch” or by using the online report form.