European hornets are large insects, measuring 3/4 to 1 3/8 inches long. Although they are not naturally aggressive, they have the potential to sting if they feel threatened. These hornets feed on various insects, including yellowjackets, butterflies, and bees source.
As a woodland species, European hornets prefer natural cavities such as tree hollows for constructing their nests. These insects typically don’t cause problems in natural areas, but they may take up residence in barns, sheds, or attics in some cases source. Foraging European hornets pose little hazard to people unless they are provoked source.
European Hornet Overview
Physical Appearance
The European hornet, or Vespa crabro, is a large insect, typically measuring between 3/4 to 1 3/8 inches long. It has a brown body with yellow stripes on its abdomen and a light-colored face. Their black and yellow-banded abdomens also have V-shaped markings.
Habitat
- European hornets build fragile, tan paper nests
- Nests are usually found in concealed places
- Examples include hollow trees, barns, outbuildings, hollow walls of houses, attics, and abandoned bee hives
Source: University of Maryland Extension
Geographical Distribution
| Continent | Presence |
|---|---|
| Europe | Native |
| Asia | Native |
| North America | Introduced |
European hornets are native to Europe and Asia. They were first introduced to North America from central Europe and were detected in the 1840s. Since then, they have spread to most of the eastern United States, reaching as far west as Louisiana and the Dakotas.
Source: Penn State Extension
Behavior and Adaptations
Hunting Patterns
European hornets are predators that primarily hunt at night, making them somewhat nocturnal. They have a diverse diet which includes:
- Bees: European hornets often prey on honey bees.
- Flies: They also feed on other flying insects like flies.
- Wasps: Smaller wasp species like yellow jackets can become their prey.
Social Structure
The European hornet is a eusocial wasp that belongs to the Vespidae family. Their colonies include a:
- Queen: The reproducing female who lays eggs.
- Workers: Sterile female offspring who help care for the brood and maintain the nest.
- Drones: Male hornets that mate with the queen, dying soon after mating.
Nesting Habits
European hornets build fragile yet characteristic nests, typically in concealed locations like:
- Hollow trees
- Barns
- Outbuildings
- Hollow walls of houses
- Attics
- Abandoned bee hives
The nests are made of tan paper constructed from chewed wood fibers mixed with saliva, forming hexagonal cells in which the queen lays her eggs.
Winter Survival
Only mated queens survive the winter in sheltered locations, such as under tree bark or in crevices. In the spring, each queen starts a new nest without reusing old ones. The survival of queens during winter ensures the continuation of the species the following year.
The European hornet is a fascinating and important predator in its ecosystem. As a nocturnal hunter, the hornet preys on many other insects, playing a key role in maintaining a balance among species. With specific nesting habits and a social structure that ensures their survival, European hornets have adapted well to their environment.
Stinging and Risks
Sting Frequency and Aggressiveness
European hornets are a type of social wasp. While not naturally aggressive towards humans, they might sting if they feel threatened. Some factors that could trigger a sting include:
- Swatting at the hornet
- Disturbing their nest
- Sweat or strong scents on your body
Comparing European hornets to other stinging insects:
| Insect | Aggressiveness | Sting Frequency |
|---|---|---|
| European Hornet | Low | Low |
| Yellowjacket | Medium | Medium |
| Honeybee | Low | Low (single sting) |
Sting Effects and Treatment
A European hornet sting can cause localized swelling and pain. To treat a sting:
- Remove stinger, if present (only honeybees leave a stinger)
- Clean the area with soap and water
- Apply a cold pack for 15-20 minutes
Over-the-counter pain relief medication like ibuprofen can help in managing the pain.
Allergic Reactions
In some people, European hornet stings could trigger an allergic response, leading to symptoms such as:
- Trouble breathing
- Anaphylaxis
- Nausea
- Fainting
In case of an allergic reaction, promptly seek medical help. Some individuals might need an Epi-pen or other medical treatment to counter the effects of the sting.
Prevention and Control
Protecting Your Home
To prevent European hornets from entering your home, ensure that all entry points are sealed. For example:
- Seal gaps around windows and doors.
- Install window screens.
- Close up wall voids and other openings.
Additionally, limit hornet attraction by following these practices:
- Don’t leave food outdoors and cover trash bins.
- Turn off porch lights at night as they attract insects.
Safely Removing Nests
European hornets build fragile, tan paper nests in concealed places such as hollow trees, barns, attics, and abandoned bee hives. If you discover a nest:
- Wear protective gear, such as gloves and goggles.
- Keep a safe distance and don’t disturb the nest.
- Use a hose to spray water and dislodge the nest, if it’s accessible.
- Repeat the process until the nest is removed.
Remember, do not attempt to remove large or inaccessible nests on your own.
Pros of this method:
- No chemicals involved.
- Affordable.
Cons of this method:
- Can be dangerous for inexperienced individuals.
When to Involve a Pest Control Professional
Certain circumstances require the expertise of a pest control professional:
- If nests are located in hard-to-reach places or pose a threat to your family.
- If hornets have entered your home and established a nest in wall voids or attics.
- In case of large infestations or multiple nests.
Professionals have access to specialized equipment, materials, and knowledge required to tackle European hornet issues effectively and safely.
Comparison of Do-It-Yourself (DIY) vs. Pest Control Professional:
| Aspect | DIY | Pest Control Professional |
|---|---|---|
| Cost | Low | Higher |
| Safety | Risky | Safer |
| Expertise | Limited | High |
| Effectiveness | Varies | Higher |
Remember, as European hornets are a social wasp species, it’s essential to handle them with caution. Don’t take unnecessary risks, and seek professional help when required.
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18 Comments. Leave new
I was just looking for something on the web when I found the site. The dragonfly seen being eaten by the hornet appears to be a swamp darner (Epiaeschna heros).
Yes, it is Epiaeschna heros. Black abdomen with alternating double and single green rings pretty much nails it.
They’re known here for their lack of aggression towards humans. Insects are a different matter though!
Thanks Juliet,
Any theory on why the Dragonfly was killed and then abandoned?
There is a lot that has been said about European Hornet and some are myth, like their supposed aggressivity toward human.
At my parents’ house we had once a busy European Hornets’ nest under the outside roof, over the balcony, jute above the table we ate at. Not even once we had been annoyed by a hornet buzzing around the food. Not only that but there wasn’t any wasp or fly around for they were exterminated by the Hornets.
The Dragonfly is to me a female Swamp Darner Epiaeschna heros.
Why the hornet has acted so I can’t tell but maybe something in the dragonfly’s behaviour has trigged a killing reflex to the Hornet, then maybe it ‘realized’ there was to much to deal with.
Thanks so much for your valuable first hand perspective.
You said not sure if they’re as far north as Maryland. For years I’ve seen these giants in south jersey. All summer long. Not just at home but all over south jersey as I travel for work in construction I’m outside all day I should have figured they weren’t native.
Our uncertainty was regarding the Dragonfly. Based on BugGuide date, the European Hornet is found as far north as Canada.
We see these too. We live in the Poconos. They slam into our Windows at night.
It should be noted that hornets (and most wasps in general) will release a pheromone when killed that attracts and enrages others from the nest. Yet another reason to leave them in peace.
Hello, my name is Cael and I am 11 and I think this hornet killed and abandoned the swamp darner because it never wanted to eat the dragonfly, I think maybe because dragonflies are predators th dragonfly was going to attack the hornet but the hornet instead decided to defend itself by attacking and killing the dragonfly then flying off
How do they nest? I found a white substance in my window frame that looks like a cigareete filter and it had “brown seed looking” eggs buried within it. I used a screwdriver to dislodge it and they fell to the ground. Scary. It was shorty after that when I turned on a lamp at my desk that one of those scary wasp like yellow jacket that was huge, stung me. It was very painful.
According to BugGuide: “Queens emerge from hibernation during the spring, and they search for a suitable location in which to start a new nest. They build the nest with chewed wood pulp, and a few eggs are laid in individual paper cells; these eggs develop into non-reproductive workers. When 5-10 workers have emerged, they take over the care of the nest, and the rest of queen’s life is devoted solely to egg laying. The workers capture insects, bringing them back to the nest to feed the brood. Workers need more high-energy sugary foods such as sap and nectar, and hornet larvae are able to exude a sugary liquid which the workers can feed on. The nest reaches its peak size towards mid September. At this time the queen lays eggs that develop into males (drones) and new queens, she then dies shortly after. The new queens and males mate during a ‘nuptial flight’, after which the males die, and the newly mated queens seek out suitable places in which to hibernate; the old nest is never re-used.” Here is an image of a European Hornet Nest from BugGuide.
I just saw one bouncing around my porch light here in western NJ. This is the second one I’ve seen this year. The first one was fluttering about on the porch floor a month or so ago, so I stomped him. Yes, my reaction both times has been “murder hornets!!!”, and these are huge, easily 1 1/2″ long and at least as thick as a pencil. Other places online say the European hornet is only an inch long. No way. The abdomen on this thing is an inch, plus the rest of the bug. I’m pretty sure I’ve seen them around our village in years past, a few blocks from here, before the murder hornet thing, and they really are big. Much bigger than the bald faced hornets we’ve got here for the first time ever this year. Maybe what I’m seeing is a cicada killer, but “flies at night, comes to the light” is something I’ve read only applies to the euro hornet?
Just found two of them early this morning. One was dead and the other was just setting on a jug, there is a light that stays on at night so I’m assuming they were attracted to the area. I took photos and it’s definitely a European Hornet. Never seen one setting still but it is very damp and cool today here in central Kentucky.
I live in NW Arkansas and the last month I have had at least 6-10 buzzing around my front porch light. They are European hornets and they are scary and 1″ long. I had someone come spray around the house and porch for the red wasps I had and these guys died and there were 70 of them. Now each morning I find 6-12 a day. I am going to try to use an attractant with a bottle and drown them.
I, too, am from NEPA and this year (2023) I am seeing SO many of these hornets. They gather around my porch light at night. I let my dog out tonight and 2 flew in the house. This is the second time this week. Their buzz is loud and they are pretty hard to kill, as I had to spray him repeatedly with oven cleaner and then whack several times with a broom handle. I looked all over for their nest but can’t seem to find one so I wonder how close they hunt from their nest? They are starting to be a real pain but summer is nearing end and hopefully they will go away soon.
Fallentimber PA I been killing at least 4 every night killed 9 last night still trying to locate the hive . I know someone who got stung by one and that nest was under the ground.