There are more than 18,000 different species of Hymenoptera, the bees, wasps and ants, in the United States. Of the 14,430 wasps, only a few live in colonies – and can attack people. All of them are in a family called Vespidae and include hornets, yellowjackets and paper wasps. Some of the more common types are the bald-faced hornet, the European hornet, and yellowjackets.
The largest hornets are about 1 inch long and the queen can be up to 1.5 inches long. These wasps are yellow with dark reddish-brown markings. The yellowjackets and bald-faced hornets, range from 1/2 to 4/5 of an inch in length and are yellow or white with black markings.
Bald-faced hornets, European hornets and yellowjacket wasps all live in nests or hives. Their hives are usually found on the corner of a house, next to window, or in small holes in the ground. There can also be large nests hanging from trees, or on buildings. Wasps usually return to their nests at dusk.
Bald-faced hornets house their colonies inside large nests that they build hanging from trees, bushes, vegetation, and occasionally from buildings. European hornet nests are typically built in hollow trees, but they are often found in barns, sheds, and attics. Unlike yellow jackets and bald-faced hornets, European hornets rarely build free hanging nests in unprotected areas, such as tree limbs. Yellowjackets nest in the ground or in hollow voids such as walls of structures. You might also find their nests in trees and bushes.
To prevent wasps from building nests in and around your home caulk or screen any openings on the exterior of buildings to prevent them from nesting in walls and fill in any holes in the lawn.
Yes, wasp stings cause swelling and itching in most people. Typically medical attention is not required, but on rare occasions humans can have a hypersensitive reaction which may cause swelling of the airways. This is very rarely fatal, especially if medical attention is sought soon after when symptoms appear.