Invasive Asian hornets ‘eating hundreds of insect species' in Europe

The Guardian

04-03-2025

Invasive Asian hornets are eating hundreds of different species of insects in Europe, including many which are important pollinators, researchers have warned.
The findings, from tests of the guts of more than 1,500 larvae, raise new concerns over the 'extra threat' the hornet poses to native insects already under pressure from farming, changes in land use and chemical pollution.
The study also highlights the potential impact on agriculture, with 43 of the 50 most commonly identified species in the hornet larvae's diet known to visit flowers – including Europe's three main crop pollinators.
The Asian hornet, or yellow-legged hornet, a voracious invasive, is native to south-east Asia. It arrived in France in a cargo of pottery from China about 20 years ago and spread rapidly across the continent.
Its main prey is honeybees. The Asian hornet can kill 50 bees a day and has devastated colonies in France and Italy.
It was first seen in the UK in 2016, and there have been regular sightings since, including 44 confirmed in 2024 – largely in Kent and East Sussex.
The researchers from the University of Exeter carried out genetic analysis in a method called 'deep sequencing' to identify prey species in the guts of more than 1,500 hornet larvae from 103 nests in Jersey, France, Spain and the UK.
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They identified 1,449 different prey which had been fed by adult hornets to their larvae in the nests, more than half of which (55%) could be identified as a specific species.
Prey included a wide range of flies, wasps, bees, butterflies, moths and spiders, with honeybees, common wasps and blowflies most commonly found.
While the hornets have a preference for honeybees, which were found in all nests and almost all samples, a wide range of other species were also recorded, showing they are 'opportunistic' and prey on any creatures that are abundant in the areas near their nests.
Europe's top three crop pollinators – the honeybee, buff-tailed bumblebee and red-tailed bumblebee – were all found among the top 50 prey species identified.
The study's lead author, Siffreya Pedersen, said: 'Asian hornets are known to prey on honeybees, but until now the full range of their diet hasn't been tested. The diet varied strongly over the seasons and between regions, showing that they are highly flexible predators.
She said: 'Insects play vital roles in enabling ecosystems to function – including pollination, decomposition and pest control. Most insect populations are in decline due to factors such as habitat destruction and chemical pollution. The expanding area inhabited by Asian hornets poses an extra threat.'
The study is published in the journal Science Of The Total Environment.