Yellow-Legged Asian Hornet (YLH)

In late November a resident of Swyre noticed a strange looking nest high up in a tree. The nest had the same look as a wasp nest but was much bigger and in a more exposed position than a wasp nest would usually be found.

The resident reported the nest to the National Bee Unit (part of DEFRA) and the nest was taken down for analysis.

The nest was made by the yellow legged Asian hornet. This invasive species is a highly efficient predator and was first found in France in 2004. It probably arrived in a consignment of pots from China. Since then, it has spread into much of Northern Europe and since 2016, England and lately, Ireland. In England in 2025 there were 161 nests found with 544 individual sightings, more than the previous six years combined.

It is a voracious predator which poses a significant threat to honeybees and all native insects – it has no natural predators in the UK.

An average nest can consume over 11kg of insects per year. While it majors on eating bees and wasps it will also take a wide variety of other insects. This has an impact on the ecology of the local area. It has already altered the biodiversity in France.

A single hornet is unlikely to cause injury if left alone, but they can become very aggressive if their nest is disturbed – keep a distance of at least 10 metres away.

This hornet is not just a problem for beekeepers, so we need eyes on the ground everywhere – in towns and cities, parks and woodland areas, ports, marinas, garden centres, orchards, vineyards, parks, timber yards, fruit and veg wholesalers, transport hubs and gardens.

Sightings should be reported, complete with an image, if possible, via the Asian Hornet Watch app - available on app store for Android and iPhone. Locally, contact your local Asian hornet team at asianhornet@westdorsetbees.org.uk for advice and confirmation of a sighting.

The National Bee Unit (NBU) will then follow up reports and destroy their nests.

Primary nests are roughly 5 -10 cm in diameter. These can often be found in sheds, garages, porches, bird boxes, hedgerows and brambles.

Secondary nests will be built close to primary nests, usually within 100m. These are usually found in the tops of trees, but those built lower down are a danger to those who might accidentally disturb them, e.g. those in hedges, bramble patches, utility boxes etc. They can be very difficult to spot when concealed by vegetation.

One nest can produce 350+ queens, some of which will begin new colonies the following year.

The YLH present one of the biggest threats to UK honey bees and other pollinators in a generation.