Vespa velutina, the yellow legged hornet, commonly known as the Asian hornet, is native to Asia and was confirmed for the first time in Lot-et-Garonne in the South West of France in 2004. It was thought to have been imported in a consignment of pottery from China and it quickly established and spread to many regions of France. As of December 2022, Asian hornet is established in Spain, Belgium, Netherlands, Portugal, Italy, Switzerland, Germany and Jersey. The hornet preys on a wide range of insects including honeybees, Apis mellifera and disrupts the ecological role they provide. It has also altered the biodiversity in regions of France where it is present and can be a health risk to those who have allergies to hornet or wasp stings.
In 2016, the Asian hornet was discovered in the UK for the first time, in Tetbury. After 10 days of intensive searching, the nest was found and later destroyed. In subsequent years there have been further sightings with action taken to find and destroy nests. As of January 2023, genetic analysis has shown that there is no evidence for an established population of Asian hornets in the UK and all hornets found have been likely to be from the European population rather than a new incursion from Asia.
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Appearance and biology of the Asian hornet
The Asian hornet is smaller than our native hornet, with adult workers measuring from 25mm in length and queens measuring 30mm. The abdomen is mostly black except for the fourth abdominal segment which has a yellow band. It has characteristically yellow legs which accounts for why it is often called the yellow legged hornet and its face is orange with two brownish red compound eyes.
After hibernation in spring, the queen, usually measuring up to 3 cm, will emerge and seek out an appropriate sugary food source in order to build up energy to commence building a small embryonic nest. During construction of the nest, she is alone and vulnerable, but she will rapidly begin laying eggs to produce the future workforce. As the colony and nest size increases, a larger nest is either established around the embryonic nest or they relocate and build elsewhere.
During the summer, a single colony, on average, produces 6000 individuals in one season. From July onwards, Asian hornet predation on honeybee colonies will begin and increase until the end of November and hornets can be seen hovering outside a hive entrance, waiting for returning foragers. This is the characteristic “hawking” behaviour. When they catch a returning bee, they will take it away and feed off of the protein rich thorax; the brood requires animal proteins which are transformed into flesh pellets and then offered to the larvae.
During autumn, the nest’s priorities shift from foraging and nest expansion to producing on average 350 potential gynes (queens) and male hornets for mating, however, of these potential queens, only a small amount will successfully mate and make it through winter. After the mating period, the newly fertilised queens will leave the nest and find somewhere suitable to over-winter, while the old queen will die, leaving the nest to dwindle and die off. The following spring, the founding queen will begin building her new colony and the process begins again.
In light of the Asian hornet finding in the UK in September 2016, it is imperative that you make sure you know how to recognise and can distinguish them from our native hornet, Vespa crabro – a very helpful ID sheet and poster is available to help you:
- ID Sheet
- ID Nest sheet
- ID Poster
- ID with Wasp and Bee Comparison
- ID with Wasp and Bee Comparison (Welsh)
Monitoring for the Asian hornet
Monitoring for arrival of the Asian hornet is strongly encouraged throughout the UK, but especially in areas where likelihood of arrival is considered to be highest (S & SE England). Should you wish to monitor for the hornet's arrival, some helpful tips and advice on how to make your own trap can be found on our factsheet page.
Where to report sightings
If you think you have seen an Asian hornet, please notify the Great British Non Native Species Secretariat (NNSS) immediately. In the first instance sightings should be reported through the free Asian Hornet Watch App, available for Android and iPhone.
Other methods of reporting the hornet also include using the NNSS online notification form. Finally, you can send any suspect sightings to the Non Native Species email address email@example.com. Where possible, a photo, the location of the sighting and a description of the insect seen should be included.
If you would like to know more about the Asian hornet or any other Invasive Species, the NNSS website provides a great deal of information about the wide ranging work that is being done to tackle invasive species and tools to facilitate those working in this area.
It is also important that beekeepers sign up to BeeBase. In the event that the Asian hornet (or any other exotic threat to honeybee colonies) arrives here, efforts to contain it will be seriously jeopardised if we don’t know where vulnerable apiaries are located.
Useful media links
Please do not confuse the Asian hornet, Vespa velutina with the Giant Asian hornet (Vespa mandarinia), sometimes referred to as the "Japanese hornet".
APHA Science blog - Safeguarding with Science: Responding to an Asian hornet Outbreak.
Asian Hornet Awareness and Identification for Pest Controllers.
Details about Vespa crabro, the European hornet commonly found in the UK, can be viewed on this leaflet.
To help distinguish between the many Vespa species, the French Museum of Natural History has produced an Identification Information Sheet.
In the event that the Asian hornet should arrive in Great Britain, a Contingency Plan for dealing with it has been produced and can be found below:
In order to get the latest information regarding the current Asian hornet outbreak, please visit the Gov.uk rolling news page here.