The bald-faced hornet colony has a complex, annual life cycle. Most of the colony perishes during the winter, but the species survives through a specialized mechanism. Understanding this process requires looking closely at the insect’s identity and its yearly reproductive strategy.
What is a Bald-Faced Hornet
The bald-faced hornet (Dolichovespula maculata) is technically a species of aerial yellowjacket, though it is one of the largest North American wasps. Its common name comes from its distinct black-and-white coloration, featuring ivory-white markings on its face, thorax, and abdomen. This pattern easily distinguishes it from typical yellow-and-black yellowjackets.
Workers typically measure 12 to 14 millimeters in length, while queens reach up to 20 millimeters. These social insects build large, enclosed, gray paper nests, often high up in trees or on buildings. They serve an ecological role as predators, foraging for other insects and arthropods to feed their developing larvae.
The End of the Annual Colony Cycle
The life of a bald-faced hornet colony is constrained to a single season. As warmer months transition into late autumn, the population, which can number in the hundreds, begins to decline. This decline is triggered by dropping temperatures and the diminishing availability of food sources needed to sustain the large worker population.
The original queen, who started the nest in the spring, stops laying eggs and eventually dies from old age or cold exposure. The infertile female workers, who spent the season foraging and expanding the nest, also perish. Males, or drones, whose function is to mate with the new queens, die off after mating is complete.
This mass die-off is the planned conclusion of the colony’s reproductive cycle. By the time the first hard freezes arrive, the vast majority of the inhabitants—workers, males, and the founding queen—have succumbed to the cold or old age. The nest becomes completely inactive during the winter months.
How the Species Survives Winter
The survival of the species is secured by the next generation of mated queens, produced late in the season. These reproductive females emerge from the nest alongside males for mating flights. After successfully mating, these new queens do not return to the original colony.
The newly mated queen prepares for a long, solitary overwintering period known as diapause. She builds up large reserves of fat, which serves as her sole energy source for the entire winter. This stored energy is crucial for surviving months without food and fueling the first phase of nest building in the spring.
The queen seeks a protected shelter to spend the winter alone in a state of quiescence, similar to hibernation. Common overwintering sites include protected crevices beneath loose tree bark, inside rotting logs, or within the voids of human structures. She remains inactive until the consistent warmth of spring signals the time to emerge and begin a new colony.
The Fate of the Paper Nest
The large, football-shaped nest, constructed from chewed wood fibers mixed with saliva, remains visible long after the inhabitants have died. This paper structure is never reused by the new queens in the following spring. Each new queen selects a new, uncontaminated location to begin her own construction.
The old nest is not insulated enough to protect a solitary queen from winter’s rigors. It may also harbor parasites or diseases that would threaten a new colony. Once winter is established and temperatures consistently drop below freezing, the nest is completely inactive and poses no threat.
The exposed paper structure gradually deteriorates throughout the winter. It often becomes tattered or disintegrates completely due to wind, rain, and snow.