Identifying insects like the bald-faced hornet, often called a “black hornet,” is important for understanding their role in our environment. This article focuses on their unique physical characteristics, how to distinguish them from similar insects, and their distinctive nesting habits, providing a clearer understanding of these insects.
Key Physical Characteristics
The bald-faced hornet (Dolichovespula maculata) is a North American species often called a “black hornet” due to its prominent dark coloration. These wasps typically measure 0.5 to 0.75 inches (12-19 mm) in length, with queens reaching 0.75 inches (18-20 mm) or more, making them notably larger than many other yellowjacket species. Their body is stout and tapers towards the rear.
Its most striking feature is a black body contrasted with white or ivory markings. The common name comes from the white pattern on its face, giving it a “bald-faced” appearance. White or ivory markings also appear on the thorax and as three stripes towards the tip of the abdomen.
Their wings are translucent, typically dark brown, and fold lengthwise when at rest. They have conspicuous antennae and six legs. Their distinct size, stout body, and sharp black and white patterns aid identification.
Distinguishing from Similar Insects
While often called a hornet, the bald-faced hornet is technically an aerial yellowjacket, not a true hornet from the genus Vespa. Yellowjackets, close relatives, are typically smaller with bright yellow and black markings. Unlike the bald-faced hornet’s black body with white, yellowjackets have more intricate yellow and black banding patterns and less robust bodies.
Paper wasps (Polistes spp.) have slender bodies with longer legs that may dangle during flight, and a distinctive thin waist. Their coloration varies, often including red-brown, black, and yellow, but they lack the prominent white facial markings.
European hornets (Vespa crabro), the only true hornet species in North America, are larger than bald-faced hornets, measuring up to 1.5 inches long. They have a distinct brown body with yellow stripes, and black bands on the abdomen often have tear-drop shaped extensions.
Bees (e.g., honey bees, bumble bees) are generally fuzzier or hairier than bald-faced hornets, which have smooth, sparsely hairy bodies. Bees also tend to have stouter bodies, wider legs, and coloring often includes shades of yellow, orange, or tan. Cicada killer wasps have black abdomens with yellow splotches and reddish eyes, appearing more slender.
Habitat and Nest Appearance
Bald-faced hornets construct distinctive nests. These social wasps build large, enclosed paper nests, typically gray or mottled gray, from chewed wood fibers mixed with saliva.
Nests are often egg-shaped or football-shaped and can grow quite large, sometimes reaching up to 23-24 inches (58-60 cm) in length and 14-30 inches (36-76 cm) in diameter by late summer. They are generally suspended from tree branches or large bushes, at least three feet off the ground, but can also be found under roof overhangs, eaves, utility poles, or on the sides of buildings. The nest usually has a single entrance hole, often located at the bottom.
Internally, these nests contain several tiers of horizontal paper combs where larvae are reared. Unlike some other wasp species, bald-faced hornets do not reuse their nests; a new one is constructed each spring by the queen.