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Asian hornets: how to spot the garden predator that threatens to destroy Britain's bees

Asian hornets: how to spot the predatory species that threatens to destroy the nations bees  - Elaine Thompson
Asian hornets: how to spot the predatory species that threatens to destroy the nations bees - Elaine Thompson

Experts have warned that Vespa velutina - the Asian hornet or yellow-legged hornet - an invasive species from Asia, could be a devastating threat to British honey bee colonies.

The non-native predatory insect is thought to have been introduced to Europe after unknowingly being transported in cargo from China to France in 2004; since then, the expansion of the species has been relentless.

Wildlife in France said: ‘Colonies have spread quickly through neighboring regions. In the initial stages, they follow rivers and other watercourses: in fact, a nest will never be found far from a source of water even if that is only a small pond.’ As of 2019, thousands of nests have been found across Spain including the north, as well as Belgium, Spain and Portugal.

“In northern Spain, two Asian hornet nests were found a couple of hundred kilometres apart,” reports BBC chief environment correspondent Justin Rowlatt.

“Within four years, there were more than 10,000 nests and each one is capable of devastating a honey bee colony.” In Galicia, northern Spain, it is reported that some bee colonies have had mortality rates of more than 50 per cent since the arrival of the Asian hornet, while the bees that survive the hornet attacks will significantly reduce honey production afterwards.

“People tell you that they are seeing a lot fewer insects, and the wasp traps confirm this," explains Carlos Valcuende, member of the Confederation to Defend Bees on the Cantabrian Coast, to Sonia Vizoso of El País. "At first very few Asian hornets were getting caught, and a lot of other species. Now it’s the other way around.”

This isn’t just an issue for Europe. The Channel Islands continue to battle against an invasion from Asian hornet colonies. In June 2019, more than 80 queen hornets were spotted in Jersey, while sightings in Guernsey continue to increase. A rising number of nests in Alderney and Sark have also been reported over the past five years.

In the UK, sightings of Asian hornets are becoming more common; the latest was confirmed near Christchurch, Dorset on October 1, 2019, and two nests were subsequently destroyed. Public sightings have also been reported in Staffordshire and Hampshire. Since 2018, there have been more than 14 confirmed nest sightings.

British beekeepers are determined to learn from what they’ve witnessed in Europe, urging the nation to educate themselves on Asian hornets: particularly, how to spot them and how to report a sighting.

“They’re fantastically successful invaders,” Lynne Ingram, master beekeeper, told the BBC. “Honey colonies are like a supermarket for Asian hornets.” Hornets will raid honeybee hives by sitting outside them and capturing workers as they go in and out, dismembering them and feeding the thorax to their young.

Keep watch: an Asian hornet nest  - Peter Kennedy
Keep watch: an Asian hornet nest - Peter Kennedy

'They are specialised honey bee predators and beekeepers are concerned,' writes Dr Gavin Broad, a wasp expert at the Natural History Museum. 'It's a distinctive enough species that people notice it - but it only takes one queen for them to make it.' Broad hopes that the public will take notice of the nests early enough to take action. 'The Asian hornet typically builds its nest in the open - they often build on tree branches in the foliage. The nest is patterned, which probably helps to disguise it among the leaves.'

Typically, sightings of the Asian hornets will increase from March, when the life cycle of the insect begins after the queen emerges from hibernation. She will then build a small primary nest and lay eggs, which then is rebuilt into a secondary nest by worker bees in May. From June to October, the public must remain vigilant for nest sightings in order to protect British honeybees, which are already in decline.

Experts warn that it would be near impossible to halt the spread of Asian hornets if they established permanent populations in the UK, but there are important steps to take if there is any chance of protecting the UK from further outbreaks. Take a look at our guide below.

How to spot an Asian hornet

Identifying Asian Hornet table - Sarah Bunker for Animal and Plant Health Agency 
Identifying Asian Hornet table - Sarah Bunker for Animal and Plant Health Agency

According to the British Bee Association, the following characteristics are common in Asian hornets:

  • Vespa velutina (Asian hornet) queens are up to 30 mm in length; workers up to 25 mm (slightly smaller than the native European hornet Vespa crabro)

  • Mostly black body except for its 4th abdominal segment which is a yellow band located towards the rear

  • It has characteristic yellow legs which accounts for why it is often called the yellow legged hornet. Face is orange with two brownish red compound eyes

  • Vespa velutina is a day flying species which, unlike the European hornet, ceases activity at dusk

Report any suspect sightings

If you think you've seen an Asian hornet,  report the sighting using the iPhone and Android app ‘Asian Hornet Watch’, by filling out an online report form or by emailing alertnonnative@ceh.ac.uk.

If you suspect you have seen an Asian hornet you should report this using the ‘Asian Hornet Watch’ app:

Please include a photograph, information on location, date and number of Asian hornets you have seen, this way experts at National Bee Unit ( NBU ) and the Animal and Plant Health Agency ( APHA) can act quickly to find and destroy any active nests in the area.

Should I remove it myself?

If you find a nest, do not try to disturb or remove it in any way.

Doing so can cause the colony to become aggressive, risking harm to yourself and others. The UK government advises that if you do find a nest, do not remove it yourself. Leave it to the experts.

What to do if you keep bees

If you keep bees, you should read up on the following information available from The National Bee Unit.

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