Bald Faced Hornet

Learn About Bald Faced Hornet


Baldfaced hornets are distinguished from other yellowjackets by their white and black coloring. It has a white or "baldfaced" head, which is the source of its colloquial name. These wasps also have three white stripes at the end of their bodies. They are notably larger than other species of Dolichovespula, as adults average about 19 millimetres (0.75 in) in length.[4] Queen and worker wasps have similar morphologies. Queens are always larger than workers in their colonies, though size distributions can vary in different nests and workers in one colony might be as large as a queen in a different one.[1]

D. maculata create egg-shaped, paper nests up to 360 millimetres (14 in) in diameter and 580 millimetres (23 in) in length. Nests are layered hexagonal combs covered by a mottled gray paper envelope. bald-faced hornets create this paper envelope by collecting and chewing naturally occurring fibers. The wood fiber mixes with their saliva to become a pulpy substance that they can then form into place.[4]


The bald-faced hornet lives in North America, including Canada, the Rocky Mountains, the western coast of the United States, and most of the eastern United States. It is most common in the southeastern United States.[3]

Dolichovespula maculata is found in forested areas and in vegetation in urban areas. Nests are generally located in trees and bushes but they can occasionally be found under rock overhangs or the sides of buildings. Vertical distribution of nests has been recorded from heights of 0.3 to 20 m (1 ft 0 in to 65 ft 7 in) above ground level.[5]


Bald-faced hornets are omnivorous and are considered to be beneficial due to their predation of flies, caterpillars, and spiders. However, their aggressive defensive nature makes them a threat to humans who wander too close to a nest or when a nest is constructed too close to human habitation. They vigorously defend the nest, with workers stinging repeatedly, as is common among social bees and wasps. However, the baldfaced hornet has a unique defense in that it can squirt or spray venom from the stinger into the eyes of vertebrate nest intruders. The venom causes immediate watering of the eyes and temporary blindness.[6]

Colony Cycle

The life cycle of a colony can be divided into the founding stage, the ergonomic stage and the reproductive stage.[7] Colonies show annual cycling. New nests are generally founded during spring and early summer by a single queen, though temporal specifics vary depending on location. In Washington State, nest initiation occurs during mid-May, and workers emerge during mid-June. Large cell building starts during mid-July, and the first queens emerge during mid-August. The colony terminates during mid-September, for a life cycle of approximately four months (122 days).[5] Lower latitudes correlate with longer life cycles. In Indiana, colonies were observed to begin in early May and terminate in late September, a life cycle of five months (153 days), and in Central California nests are initiated as early as the end of March. These nests survive between 155 and 170 days.[5] Active colonies have been observed in central Pennsylvania as late as mid-October.

Life Cycle

Each spring, queens that were born and fertilized at the end of the previous season begin new colonies. A queen selects a location for its nest, begins building it, lays a first batch of eggs and feeds this first group of larvae. These become workers and assume the chore of expanding the nest. They chew up wood, which mixes with a starch in their saliva. They then spread it around with their mandibles and legs, and it dries into a papery structure. The workers guard the nest and feed on nectar, tree sap and fruit pulp (particularly that of apples). They also prey on insects and other arthropods, chewing them up and feeding them to the larvae. They have been known to scavenge raw meat. In late summer and early fall, the queen begins to lay eggs which will become drones and new queens. After pupation, these fertile males and females fly off to mate. Fertilized queens then overwinter and start new colonies during the next year.

Males and workers die in the end of the cycle. The old queen, if not killed by workers, dies with them around mid-autumn.