Asian hornet

The yellow-legged Asian hornet, Vespa velutina nigrithorax, is a social wasp native to Asia that has become, in twenty years, one of the main concerns of beekeepers in Western Europe. It is not a disease but a predator. It catches bees in front of hives, but above all it frightens colonies, to the point that they stop foraging just when they should be building up their winter stores^{1, 6}.

Where it is established, eradication is no longer realistic: the French national plan now aims to limit its impact⁴. This factsheet covers its biology, its effects on colonies, the protective methods that have been studied, nest removal and the legal framework.

An invasion that began with a single queen

The species was accidentally introduced into Lot-et-Garonne, in south-west France, where it has been known since 2004, probably arriving with pottery imported from China⁴. Genetic analyses indicate that the European invasion descends from very few females, possibly a single queen mated with several males. The most likely source is eastern China, between the provinces of Zhejiang and Jiangsu. The population established in South Korea comes from a separate introduction⁵.

Since then it has spread across almost all of France and into several neighbouring countries.

Biology: a yearly cycle in four stages

As with the European hornet, only the young mated queen survives the winter. The rest of the colony dies in autumn¹.

1. Founding queens emerge (late winter, spring). Queens leave their winter shelter as temperatures rise. The French national plan puts peak emergence around mid-April⁴. Each founding queen builds a small primary nest on her own, often in a sheltered spot (garden shed, eaves, hedge), and rears her first larvae there. This is the most fragile stage of the cycle.
2. First workers (late spring). Once the first workers emerge, the queen stops leaving the nest. The colony often moves to a secondary nest, much larger, frequently high up in a tree and hidden by foliage until autumn.
3. Growth (summer). The secondary nest keeps growing. At its peak a nest can hold several thousand individuals¹. The larvae’s need for protein soars, and pressure on apiaries becomes heavy.
4. Production of males and queens (late summer, autumn). The nest produces males and future queens. After mating, the young fertilised queens leave to overwinter alone. The nest empties and is never reused.

What it eats

Adults feed mainly on sugary liquids: nectar, ripe fruit, honeydew. The prey they catch is used to feed the larvae, which need protein. The Asian hornet is a generalist hunter: according to a study in France, honey bees make up a large but variable share of its prey depending on the habitat, the rest consisting mostly of flies and other Hymenoptera¹¹.

Hunting by hovering

In front of an apiary, workers show a typical behaviour: they hover a few tens of centimetres from the entrance, facing the hive, and wait for loaded foragers returning home. They seize them in flight, land on a nearby branch and carry only the muscle-rich thorax back to the nest, as a pellet¹.

Why it matters for colonies

Foraging paralysis

The number of bees killed is not the whole story. A study in France measured two effects near hives under attack: foragers that fail to return home, and above all foraging paralysis. With hornets patrolling, the colony reduces or even stops its flights. The study’s simulations showed that this paralysis, more than direct predation, best explains the winter collapse of stressed colonies⁶.

Less pollen and nectar coming in means less brood, fewer winter bees and depleted stores: the colony goes into winter too small (see Winter losses).

Losses in figures

Nucs, mating nucs and weak colonies are the most vulnerable. A recent study estimated that in France, under a high-predation scenario, hornet-related losses could reach nearly 30% of beekeepers’ colonies each year, and that replacing them would cost more than a quarter of honey revenues¹⁰. These are projections for heavily affected areas, not general averages.

Identification and look-alikes

The Asian hornet is smaller than the European hornet. Its body is about 2 to 2.5 cm long¹³.

The European hornet is a native species with a useful role in ecosystems. It is often caught by mistake in non-selective traps⁸: telling the two apart avoids killing it for nothing.

Spotting an attack and finding nests

The signs of an attack at the apiary are easy to recognise:

• several hornets hovering in front of the hives, especially late morning and in the afternoon;
• very little flight activity in good weather, while colonies not under attack are foraging.

To find the nest, watch the direction taken by hornets carrying prey: they fly back to their nest in a fairly straight line. In autumn, leaf fall reveals many nests, often too late.

Regulatory framework

European Union

Vespa velutina nigrithorax has been on the list of invasive alien species of Union concern since 2016². Member States must put management measures in place.

France

Law no. 2025-237 of 14 March 2025 provides for a national control plan, implemented through departmental plans under the authority of prefects, and for a compensation scheme for beekeepers who have suffered economic losses. Its implementing decree of 29 December 2025 sets out how these plans are adopted and updated³.

The national plan, adopted by an order of 9 September 2026, classifies departments into four levels according to the density of nests detected. It sets recommendations on trapping, apiary protection and nest removal, and plans to bring reports together on a single platform hosted by the INPN (national natural heritage inventory)⁴. Departmental plans must set out the local reporting and removal procedure.

The hornet is not classified as a health hazard: there is no compulsory notification as there is for American foulbrood. Meat-based baits soaked in insecticide are strictly prohibited⁴.

Distribution worldwide

Outside its native Asian range, the Asian hornet is present, according to EPPO, in France, Spain, Portugal, Italy, Belgium, the Netherlands, Luxembourg, Switzerland, Germany and the Channel Islands. In the United Kingdom, where EPPO classes it as transient, incursions are treated as outbreaks to be eliminated¹²; every sighting must be reported to the authorities. Rules vary from country to country. In Asia, it is invasive in South Korea and locally present in Japan. In the United States, a first nest was detected in Savannah, Georgia, in 2023¹³.

Protection: what the studies say

No single method is enough. Hive protection, strong colonies and collective action against nests need to be combined.

Entrance guards and reduced entrances

An entrance guard, or muzzle, is a mesh cage or tube placed in front of the entrance. Bees pass through; the hornet can no longer hunt right at the landing board. In a trial comparing 22 pairs of colonies in France, the muzzle sharply reduced foraging paralysis, without reducing the loss of foragers in flight. The associated simulations showed a significant survival gain for colonies under heavy pressure⁷. It is the basic method, with no effect on other insects.

The French national plan also recommends reducing entrances, to the narrowest setting from October⁴.

Electric harps

A harp is a frame of electrified wires placed near the hives. Patrolling hornets touch the wires and fall into a tray. A 2023 study found them efficient and selective against workers hunting in front of hives⁹. The French national plan recommends them alongside muzzles, at roughly one harp per five hives⁴. They need a power supply and monitoring.

Trapping: useful only when targeted

Trapping is the most debated point. A study in Spain on baited spring traps found that the Asian hornet made up less than 1% of the insects caught. For every hornet trapped, the traps killed on average more than a hundred other insects, mostly flies. The authors concluded that this method, on its own, is not effective⁸.

The French national plan therefore sets out a controlled approach to trapping⁴:

• in spring, against founding queens, for two months at most around the mid-April peak, starting once temperatures exceed 12 °C, near apiaries and attractive flowers;
• from August to the end of November, only at apiaries under heavy pressure;
• using traps with physical selection, which let small insects escape, and sugary baits without honey or wax;
• avoiding bottle, bell and jar traps.

The effect of spring trapping on the number of summer nests remains debated: it is a supplementary measure.

Strengthening colonies

A populous colony defends its entrance better. In exposed areas, weak colonies are united before the end of summer.

Nest removal

It is useful from spring to autumn, ideally before the nest releases its future queens. The French national plan states that once the founding queens have left, around 15 November as a guide, destroying a nest is no longer worthwhile⁴.

• Who? A professional pest controller or a trained local contact.
• How? Primary nests can be destroyed mechanically or by freezing. Secondary nests are treated using telescopic poles or drones that inject a biocide or steam. The plan recommends natural pyrethrins without piperonyl butoxide or diatomaceous earth, rules out permethrin and advises against paintball shots⁴.
• How to report? To the town hall or the reporting platform designated in your area. The local plan sets out the procedure and, depending on the area, who pays.

The most common mistakes

• Using non-selective bottle traps, set everywhere and all year round: they mostly kill flies, moths and other pollinators.
• Putting honey or wax in baits, which attract bees and spread disease.
• Fitting muzzles too late, when the colony is already paralysed and has lost its foragers.
• Relying on trapping alone and neglecting entrance protection.
• Destroying a high nest yourself, with a serious risk of multiple stings and falls.
• Having a nest destroyed in December, after the future queens have already left.
• Confusing the European and the Asian hornet, and killing a native species for no reason.

Frequently asked questions

Do muzzles bother the bees? They slow traffic at the entrance a little, but bees get used to them quickly. The French study that tested them shows they sharply reduce foraging paralysis⁷.

Is an empty nest in winter dangerous? No. A nest found in midwinter is usually abandoned: the queens have left to overwinter elsewhere, and it will not be reoccupied. Destroying it no longer helps control.

Is the Asian hornet more dangerous to people than the European hornet? Away from its nest, it is not aggressive. Near the nest, it defends its colony and may sting in numbers. People with allergies should take extra care.

Who pays for nest removal? It depends on the area. In France, the 2025 law and the national plan provide for public funding of control, but the details of who pays are set locally: ask your town hall. Elsewhere, check with your national or local authorities^{3, 4}.

References

1. Monceau K., Bonnard O., Thiéry D. (2014). Vespa velutina: a new invasive predator of honeybees in Europe. Journal of Pest Science 87: 1-16. doi.org
2. Commission Implementing Regulation (EU) 2016/1141 adopting a list of invasive alien species of Union concern. eur-lex.europa.eu
3. France: Law no. 2025-237 of 14 March 2025 on curbing the spread of the yellow-legged hornet; Decree no. 2025-1377 of 29 December 2025 (in French). assemblee-nationale.fr
4. France: National plan to control the yellow-legged hornet (annex to the order of 9 September 2026, in French). aida.ineris.fr
5. Arca M., Mougel F., Guillemaud T., Dupas S., Rome Q., Perrard A. et al. (2015). Reconstructing the invasion and the demographic history of the yellow-legged hornet, Vespa velutina, in Europe. Biological Invasions 17(8): 2357-2371. doi.org
6. Requier F., Rome Q., Chiron G., Decante D., Marion S., Menard M., Muller F., Villemant C., Henry M. (2019). Predation of the invasive Asian hornet affects foraging activity and survival probability of honey bees in Western Europe. Journal of Pest Science 92(2): 567-578. doi.org
7. Requier F., Rome Q., Villemant C., Henry M. (2020). A biodiversity-friendly method to mitigate the invasive Asian hornet's impact on European honey bees. Journal of Pest Science 93: 1-9. doi.org
8. Rojas-Nossa S.V., Novoa N., Serrano A., Calviño-Cancela M. (2018). Performance of baited traps used as control tools for the invasive hornet Vespa velutina and their impact on non-target insects. Apidologie 49(6): 872-885. doi.org
9. Thiéry D., Doblas-Bajo M., Tourrain Z., Le Provost G., Núñez-Pérez E. (2023). Electrical traps, so called harps, efficient and selective against Vespa velutina workers predating on hives. Entomologia Generalis 43(5): 945-950. doi.org
10. Requier F., Fournier A., Pointeau S., Rome Q., Courchamp F. (2023). Economic costs of the invasive Yellow-legged hornet on honey bees. Science of the Total Environment 898: 165576. doi.org
11. Rome Q., Perrard A., Muller F., Fontaine C., Quilès A., Zuccon D., Villemant C. (2021). Not just honeybees: predatory habits of Vespa velutina (Hymenoptera: Vespidae) in France. Annales de la Société entomologique de France 57(1).
12. EPPO Global Database. Vespa velutina (VESPVE): geographical distribution. gd.eppo.int
13. USDA APHIS. Yellow-legged hornet (US detection, identification). aphis.usda.gov
14. USGS Bee Inventory and Monitoring Lab. Vespa crabro, female, side view (public domain). usgs.gov

Updated : October 8, 2026
Written by : Apisanitas editorial team
Reviewed by : Review in progress