Bald-faced hornets, despite their common name, are actually a species of yellowjacket, known for their distinct black and white markings and large, gray, paper-like nests. They are found throughout North America, particularly in the southeastern United States. These social insects live in colonies that can grow quite large during warmer months, sometimes reaching 400 to 700 workers. As the seasons change and cooler temperatures arrive, a common question arises: where do bald-faced hornets go in the winter?
The Colony’s Winter Demise
When winter approaches, the vast majority of a bald-faced hornet colony faces its natural end. The worker hornets, drones (males), and the old queen do not survive the cold temperatures and diminished food sources. Their bodies, being cold-blooded, struggle to regulate temperature as it drops below 50 degrees Fahrenheit, severely impacting their ability to fly and forage. This decline in activity and lack of sustenance leads to their eventual demise, often through freezing or starvation.
This mass die-off is a regular part of their annual life cycle. The large, paper nests, often seen hanging from trees or utility poles, are abandoned and will not be reused in subsequent years. These structures become prominent after leaves fall.
The Queen’s Solitary Survival
While the colony perishes, a select few individuals ensure the species’ continuation: the newly fertilized queens. These queens are the sole survivors, entering a state of hibernation. Their survival hinges on finding well-insulated locations that offer protection from freezing temperatures and potential predators.
These overwintering sites are diverse, commonly including concealed spaces such as under loose bark on trees, within hollow logs, or buried deep in leaf litter on the forest floor. They may also find shelter in human-made structures, utilizing protected crevices in attics, wall voids, or under roofing tiles.
Once settled, the queen enters a state of diapause, a period of suspended development. During this inactive phase, the queen’s metabolism significantly slows, allowing her to conserve stored energy reserves and endure months without foraging for food. This physiological adaptation is necessary, as her body temperature largely reflects her surroundings. To prevent internal ice crystal formation, some queens produce a natural glycerol, acting as an antifreeze. They remain in this torpid state until the consistent warmth of spring signals re-emergence.
Re-emergence and New Beginnings
As spring arrives and temperatures consistently rise, the hibernating queens begin to stir from their solitary dormancy. Typically in April or May, they emerge from their overwintering sites, driven by the increasing warmth. The queen’s first action is to search for a suitable location to establish a new nest.
She selects a site, often in trees, large shrubs, or sometimes under the eaves or siding of buildings. Using her mandibles, she gathers wood fibers, chews them, and mixes them with saliva to create a paper-like pulp. With this material, she constructs a small, initial paper nest, typically plum-sized, containing a few hexagonal cells.
Within these first cells, she lays her initial batch of eggs, usually one per cell. These eggs hatch into larvae, which the queen feeds with chewed insects until they pupate and mature. The first offspring to emerge are sterile female workers, who then assume the duties of expanding the nest, foraging for food, and caring for subsequent generations.
This cooperative effort allows the colony to grow rapidly throughout the summer, continuing the annual cycle of bald-faced hornet life.