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Asian hornet

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. The hornet preys on honeybees, Apis mellifera and disrupts the ecological role which it provides and damages commercial beekeeping activities. 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 and on the same day, a single hornet was discovered in a bait trap in North Somerset. Genetic analysis has confirmed that the hornet nest found in Tetbury and the dead hornet found in North Somerset were of the same genetic population (Vespa velutina nigrithorax) as those which came from Eastern China to France. Although we cannot rule out the hornet arriving directly from the same area in China, we believe this is highly unlikely.

Appearance and biology of the Asian hornet

Appearance and biology of the Asian hornet

Vespa velutina
(Asian hornet) is smaller than our native hornet, with adult workers measuring from 25mm in length and queens measuring 30mm. It's abdomen is mostly black except for it's fourth abdominal segment which is a yellow band located towards the rear. It has characteristical yellow legs which accounts for why it is often called the yellow legged hornet and it's face is orange with two brownish red compound eyes.

Spring
After hybernation 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 energry 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.

Summer
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.

Autumn
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 1

ID Poster



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). We strongly encourage that all beekeepers monitor for the Asian hornet. Some helpful tips and advice on how to make your own trap can be found in our fact sheet 'An Asian hornet monitoring trap' and on our youtube video How to make an Asian hornet monitoring trap.

Information from beekeepers in France shows that nest numbers can be reduced over time by > 90% in areas where traps are deployed in springtime coupled with IPM techniques and nest location and destruction. Should the Asian hornets become established in the UK, springtime trapping will thus be a very useful management tool. When hanging out traps, please remember that it is important that damage to native wasps, hornets and any other insects is kept to an absolute minimum.


Where to report sightings and send in samples

Where to report sightings and send in samples

If you think you have seen an Asian hornet, please notify the Great British Non Native Species Secretariat (NNSS) immediately. In the first instance their online notification form should be your first port of call by supplying a photo if possible. There are however other methods of reporting any suspect sighting which include an alert email address at . If you are interested in monitoring for the early detection of the species, the NNSS have developed a new app called Asian Hornet Watch, which allows you to take photos and submit the location of your siting using GPS.

Additionally,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.

Finally, if you suspect that you have found an Asian hornet, you can send a suspect sample to the NBU laboratory for examination. Use a suitable sturdy container (cardboard rather than plastic) and provide as much detail as possible about the hornet and where you found it. See How to Send Samples into the Laboratory page. Digital photographs are also very useful to help with identification.


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".
  • The Animal and Plant Health Agency has set up a YouTube channel where the National Bee Unit has shared videos of our experience encountering the Asian Hornet in Andernos-les-Bains, South West France.
  • BeeCraft magazine published a detailed article covering the lifespan, habitat and spread of the Asian hornet through France. Please see the article Vespa velutina The Asian Hornet which also covers the impact on agriculture and honey bees. Follow-up articles have been produced in September and October 2011. These can be viewed here;
  • Biologist Magazine published an article in May 2009 A foreigner in France: the Asian hornet written by Marie-Pierre Chauzat of the French Food Safety Agency and Stephen Martin from the University of Sheffield. We thank the authors for allowing us to attach this piece;
  • Aliens- The Invasive Species Bulletin (Issue No 31, 2011) titled: Monitoring and control modalities of a honeybee predator, the yellow-legged hornet Vespa veluntina nigrithorax (Hymenoptera: Vespidae);
  • A French article La découverte du Frelon asiatique Vespa velutina, en France (The discovery of the Asian hornet Vespa velutina in France) written by Claire Villemant and R Jean Haxaire from the French National Museum of Natural History and R Jean-Claude Streito from the French National Laboratory of Plant Protection - Entomology Unit.


Further reading

  • Details about Vespa crabro, the hornet commonly found in the UK, can be viewed here. (For useful advice on the conservation of bees, wasps and ants within Great Britain and Ireland, visit Hymettus Ltd. The national society dedicated to studying and recording bees, wasps & ants (aculeate Hymenoptera) in Britain & Ireland is BWARS);

  • Further details on Asian hornets can be viewed on Inventaire National du Patrimoine Naturel the website for National Inventory of Natural Heritage in France;

  • To help distinguish between the many species of Vespa species, the French Museum of Natrual History have 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. The Contingency Plans objectives are:

    - Early detection of the hornet;

    - Interception and prevention of establishment;

    - Nest destruction to eradicate localised outbreaks (if within a limited geographical area or areas);

    - Development of longer term management plans where eradication is no longer possible due to the extent and number of outbreaks;

    - Provision of advice to beekeepers and all other stakeholders.