Asian Hornet (Vespa velutina): Appearance, Nest Structure, and Sting Hazards

In Europe, the Asian hornet (Vespa velutina), also known as the yellow-legged hornet or simply velutina, has become one of the most concerning invasive insect species. Over the past two decades, this large hornet has rapidly spread across coastal and humid climate areas, especially where rainfall is frequent and temperatures are mild. Due to its large population, aggressive behavior, and severe threat to honeybee colonies, it poses a triple threat to ecosystems, agriculture, and human health.

1. Appearance – How to Identify the Asian Hornet

Compared to common wasps and honeybees, the Asian hornet has several distinctive traits:

1. Size

• Workers measure 30–35 mm (3–3.5 cm) in length, significantly larger than the common wasp (about 20 mm) and the honeybee (about 15 mm).

2. Coloration

• Head: Black or dark brown, with an orange-yellow face.

• Thorax: Velvety dark brown to black.

• Abdomen: A thin yellow band on the first segment; the fourth segment is bright yellow; the rest is mostly dark.

• Legs: Yellow tips, visible even in flight.

• Wings: Smoky brown and semi-transparent.

3. Behavior

• Highly aggressive, especially when the nest is threatened.

• Hunts honeybees intensively — each worker can capture 25–50 bees daily, devastating hives and harming beekeeping industries.

2. Nest Structure and Location

Asian hornets usually build their nests high in tree canopies, but in invaded areas, they also use unconventional sites such as:

• Low shrubs

• House eaves

• Wall cavities

• Abandoned tires, sheds, or garages

Nest features:

• Size: Up to 0.8 m in diameter and 1 m tall

• Material: A paper-like pulp made from chewed wood fibers mixed with saliva

• Shape: Mostly spherical, sometimes pear-shaped

• Internal design: Contains an insulating air layer to maintain stable temperature

• Defensive behavior: Nests are heavily guarded; any nearby movement may trigger a mass attack

3. Sting Risks and Venom Toxicity

The venom of the Asian hornet is similar in composition to that of common wasps but is more dangerous due to:

• Larger body size

• Thicker stinger

• Greater venom injection volume

High-risk groups:

1. People allergic to bee or wasp stings (about 3% of the population)

2. Elderly individuals

3. Those with cardiovascular or respiratory conditions

4. Victims of multiple stings

Severe reactions may include:

• Anaphylactic shock: Swelling of the throat (laryngeal edema), difficulty breathing, and potential cardiac arrest

• In extreme cases, death can occur within minutes without medical intervention

For most people:

• Symptoms include intense pain, swelling, burning sensation

• The affected area swells more and lasts longer than a common wasp sting

4. First Aid for Asian Hornet Stings

If the victim is high-risk (allergic, elderly, with underlying conditions):

• Call emergency services immediately

• Medical staff may administer adrenaline (epinephrine), antihistamines, or corticosteroids

For non-allergic individuals:

• Move away from the nest area immediately to avoid further stings

• Rinse the sting site with plenty of clean water

• Apply a cold compress to reduce swelling and pain

• Avoid applying soil, herbs, or unsterilized remedies, as they can cause infection

5. Prevention and Control

There are no effective chemical repellents specifically for Asian hornets. The most practical approach is trapping:

DIY trap method:

• Use a container (bucket, large bottle, or jug)

• Add a sweet liquid bait (honey water, sugar water, or sugar + beer + yeast mixture)

• Add a small amount of alcohol to deter bees

• Place traps near known hornet activity areas

Natural predators include:

• European honey buzzard (Pernis apivorus)

• Bee-eater bird (Merops apiaster)

• European badger (Meles meles)

While these predators help control populations in the wild, human intervention is necessary in urban or agricultural zones.

6. Conclusion

The invasion of the Asian hornet threatens bee populations, agricultural productivity, and human safety. Recognizing its characteristics, behavior, and control methods is the first step in reducing risks. Combating this invasive species requires both scientific management and ecological balance protection.

Bibliography

Zafra, A. (07/24/2018) Homegrown R&D, key to fighting the Asian hornet plague. EFE Agency: Biodiversity.

Gamarra, L. (2016) Regulation of the Asian hornet within the framework of invasive alien species. Monfragüe Scientific Journal: Resilient Development. Volume VII(2), pp: 178-186.

EFE Verde Editorial Team (03/06/2019) The European honey buzzard, a natural support against the Asian hornet. EFE Agency: Biodiversity.

EFE Verde Editorial Team (07/13/2016) The Asian hornet, included in the EU list of invasive species. EFE Agency: Biodiversity.

animal tags： asian hornet