More than 75,000 wasp species have been documented worldwide, making wasps the most abundant group of insects on earth along with beetles. A significant number of wasp species are excessively small parasitic insects, many of which have yet to be documented by researchers. Some people are surprised to learn that many well known groups of insects, such as yellow jackets, cicada killers, and mud daubers are actually wasp species. Perhaps even more surprising, the seemingly fierce bald-faced hornet is also technically a wasp species, despite its common name. Vespa cabro is the only true hornet that inhabits the US, and this species, which is better known as the European hornet, is not native to the country. This species was introduced into New York during the 19th century, and it remains abundant in the northeastern states.

Another fact about wasps that many people find surprising is that most species nest below the ground where thousands of individual wasps protect and serve their queen. Most yellow jackets and numerous solitary wasp species frequently establish subterranean nests on residential lawns where they can pose a danger to humans. Most people are more familiar with above ground, or aerial nests that are often found attached to the upper corners of sheds, garages, and beneath the eaves of houses. While many wasp species are capable of building aerial nests, only a minority of wasp species prefer to do so regularly. In Massachusetts, the aerial yellow jacket and the bald-faced hornet are the only two potentially dangerous wasp species that generally build aerial nests as opposed to subterranean nests.

Aerial wasp nests are commonly encountered, and these grey to light brown colored nests are usually no larger than a softball in size. However, aerial wasp nests vary in size, and luckily, most of the nests people encounter are inative. The largest aerial wasp nest on record belonged to an aerial yellow jacket colony, and its proportions exceeded 30 cm in diameter and 35 cm in length. Pest control professionals should remove active wasp nests when residents encounter them on properties, as yellow jackets are relatively aggressive insects that will not hesitate to inflict repeated stings when nests become disturbed. Aerial wasp nests can be destroyed by shooting an insecticide spray directly at the nest during the nighttime hours.

Have you ever encountered an active wasp nest?