Vespa velutina male https://www.flickr.com/photos/sanmartin/
Asian Hornet (Yellow Legged Hornet)
Vespa velutina nigrithorax
Protecting UK Bees: Asian Hornet Awareness
This page will help you explore the risks Asian Hornets pose to UK ecosystems and honeybees, learn how to identify them, and find out how to report sightings effectively.
Why Asian Hornets Are Bad for the UK Environment
The Asian hornet (Vespa velutina) is an invasive non-native species that poses a serious threat to the UK’s environment, pollinators, and biodiversity.
1. They prey on honey bees and pollinators
Asian hornets are highly efficient hunters. They catch and kill honey bees, often hovering outside hives in a behaviour called “hawking.” A single hornet colony can consume thousands of bees in a season, weakening or even destroying entire colonies. They also prey on other pollinating insects such as hoverflies and butterflies.
2. They disrupt pollination and ecosystems
By reducing bee and insect populations, Asian hornets indirectly harm plant pollination, which affects crops, wildflowers, and the wider ecosystem. Fewer pollinators mean fewer fruits, seeds, and plants to support wildlife — impacting birds, mammals, and other insects.
3. They threaten local beekeeping and honey production
Attacks on apiaries cause stress and loss of colonies. Beekeepers may lose honey production and must spend extra time and money on monitoring and protection.
The Life Cycle of the Asian (Yellow-Legged) Hornet
Spring
After winter hibernation, the queen emerges and feeds on sugary foods to regain energy. She then builds a small primary nest and lays the first eggs. Once the first workers hatch, they take over nest duties while the queen continues to lay. As the colony grows, a larger secondary nest is built — often high in trees or buildings.
Summer
By mid-summer, a colony can reach around 6,000 hornets. From July to November, they prey heavily on honey bees, “hawking” outside hive entrances to catch returning foragers. The workers feed bee thoraxes and other insects to their developing larvae as a rich protein source.
Autumn
As temperatures cool, activity shifts to producing new queens and males. Each nest can generate hundreds of potential queens. After mating, the new queens leave to hibernate over winter, while the old queen and remaining colony die off. In spring, the cycle begins again.
Protecting UK Bees from the Threat of Asian Hornets
To help track and control the spread of the yellow-legged hornet, the UK Centre for Ecology & Hydrology, commissioned by Defra, has developed the Asian Hornet Watch smartphone app, available to download for iPhone or Android devices.
This app allows users to submit sightings directly into the UK’s non-native species alert system.
If you prefer, you can also report sightings using the online recording form or by emailing alertnonnative@ceh.ac.uk
Using the Asian Hornet Watch App
Easily report any sightings via the app to help monitor and manage the spread of these invasive insects.
Understanding Asian Hornet Identification
Use the app to learn to distinguish Asian Hornets from native species with clear images and detailed descriptions for easy recognition.
Reporting Sightings and Taking Action
Access online forms and guidelines to notify experts and contribute to efforts in controlling the Asian Hornet population.
How To Identify an Asian Hornet
1
Workers: 20–25 mm in length (smaller than the European hornet)
2
Very dark brown/black body and thorax
3
Abdomen mostly dark, with a distinct yellow/orange 4th segment
4
Bright yellow leg tips (key distinguishing feature)
5
Face often orange or yellowish
If You Think You’ve Seen One:
One: Stay back and do not disturb the insect or any nest.
The Asian Hornet is very likely to be extremely aggressive to any perceived danger to its nest. Please leave the destruction of any nest to an experienced professional.
Two: Take a clear photo if it is safe to do so.
A clear photo is requested to help confirm identification, as many sightings turn out to be our native European hornet, which looks similar to the Asian hornet.
Three: Report the sighting immediately
Please report it using the free Asian Hornet Watch App, available for Android and iPhone. Or use the online notification form or email alertnonnative@ceh.ac.uk