out North America, including southern Canada, the Rocky Mountains, the western coast of the United States, and most of the eastern US. They are most common in the southeastern United States. They are best known for their large football-shaped paper nest, which they build in the spring for raising their young. These nests can sometimes reach 3 feet tall. Like the median wasp (Dolichovespula media) in Europe, bald-faced hornets are extremely protective of their nests and will sting repeatedly if disturbed.
Every year, queens that were born and fertilized at the end of the previous season begin a new colony. The 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 will assume the chore of expanding the nest — done by chewing up wood which is mixed with a starch in their saliva. This mixture is then spread with their mandibles and legs, drying into the paper-like substance that makes up the nest. The workers also guard the nest and feed on nectar, tree sap and fruit pulp. They also capture insects and arthropods, which are chewed up to be fed to the larvae. This continues through summer and into fall. Near the end of summer, or early in the fall, the queen begins to lay eggs which will become drones and new queens. After pupation, these fertile males and females will mate, setting up next year's cycle of growth.
Remains of Bald Faced Hornet Nest. Image Courtesy of Makuabob.
As winter approaches, the wasps die — except any just-fertilized queens. These hibernate underground, on hollow trees until spring or other protected locations. The nest itself is generally abandoned by winter, and will most likely not be reused. When spring arrives, the young queens emerge and the cycle begins again.
Bald-faced hornets visit flowers for nectar, especially in late summer, and can be minor pollinators.
Like other social wasps, bald-faced hornets have a caste system made up, in one nest, of the following: Queen — the fertile female which 