Rise of the killer hornets

Asia's yellow-legged hornet has a toehold in Britain but we're keeping it at bay - for now

- James Fair

IT'S EARLY APRIL AND YELLOW-LEGGED, or Asian, hornet queens that managed to evade the nest-destroyers from the UK's National Bee Unit (NBU) last year are just waking up from their long winter hibernation.

Though it is native to the generally much warmer climate of south-east Asia, the yellow-legged hornet is extremely adaptable and has found continental Europe and the UK much to its liking since it arrived in France back in 2004.

A hornet queen spends April building up her reserves by feeding on sugar-rich foods, such as tree sap and nectar. She also constructs the year's first nest from rotting wood, which she mixes with her saliva to create a hollow, papier-mâché-esque ball. When that's ready, she'll lay up to 2,000 eggs, feeding them once they hatch.

And that's when she starts to wreak havoc. Because yellow-legged hornets feed voraciously on other insects, including domesticated honeybees, to satisfy their brood's requirement for protein. One nest of larvae can consume up to 11kg of insects, and it's long been feared - ever since the species was first officially recorded in Britain in 2016 - that the yellow-legged hornet could have a devastating impact not just on honeybees, but also on other pollinators, such as solitary bees, hoverflies and even bumblebees, should it become established.

Peter Kennedy, a research fellow at the University of Exeter who has been studying yellow-legged hornets since 2016, says Kennedy and his colleagues have carried out a study, due to be published this year, in which they analysed the DNA of hornet larvae to identify what the adults have been predating. They found evidence of bumblebees, even though they have also published a study that shows bumblebees - unlike other insects - are often able to escape hornet attacks.