By Donna Campbell Smith
If you’ve ever been dive-bombed by a giant hornet while you were sitting on the porch in the evening, most likely it was by a European Hornet (Vespa crabro L.). While they also hunt during the day, the reason the European Hornet can be found near outdoor lighting or bumping up against a window at night is that is where they find food. Moths and other bugs are attracted to the light and the hornets are attracted to the bugs.
Because hunting is so good near your well-lit home the hornets may also decide to build their nest close by — in rare instances within the walls of your house. They have been known to also construct their nest inside barns, out buildings, birdhouses, attached to electric meter boxes, in attics, or almost anyplace that provides an entryway and protection.
These 1-1/2 inch brown-and-yellow, carnivorous, night-hunting hornets first appeared in the United States around 1840. Starting in New York, they have since spread as far south as Louisiana and west to the Dakotas. They are the only real hornet in the United States.
The queen emerges from hibernation in the spring and starts looking for a home-site. She builds the nest just big enough to produce enough workers to take over nest construction for her. Once she has retired from nest building she concentrates on laying eggs and producing more workers. The hundreds of workers, all females, continue to make the nest bigger, hunt and bring back food.
In late summer males and females are hatched to create the next generation of queens. The old queen and the old workers die in the winter and the nest is abandoned. The new queens find a safe place to hibernate. Sometimes several queens will hibernate together.
While they appear menacing, the European Hornet is not an aggressive insect. They sting only in self-defense or to protect their nest. It is best not to swat and wave your arms at them if they happen by as this will likely be perceived as an attack.
The best way to discourage the hornets from hanging out near the house is to turn off the porch lights and draw the blinds to your windows at night. If a nest is too close for comfort it is best to have a professional remove it. The hornets will build a new nest, hopefully in a new location further from your living space.
There are some reports of European Hornets building their nest inside the walls of a house. One (anonymous) Louisburg, NC exterminator shared that, while he hasn’t encountered European Hornets inside a wall, he did have a case where they’d nested in an attic and were entering the living space through electrical fixtures. In such a case, do not close off the entrance while the hive is still active as they have been known to bore through the interior walls to get out. Then you have hundreds of the giant hornets inside the house. The good news is these are isolated cases. European Hornets usually nest in hollow trees or logs.
European Hornets are actually beneficial to humans because they eat harmful insects such as grasshoppers and crickets. Killing them should only be a last resort.
In fact, in some European counties these hornets are protected as an endangered species. So, if the hornets are not an immediate threat, it is best to leave them alone and learn to live with them.