Bald-faced hornets, despite their common name, are a type of social wasp, not true hornets. These insects are widely distributed across North America, recognized by their distinctive black bodies and white markings, especially on their faces. As social creatures, they live in organized colonies within paper nests.
Typical Colony Size
A mature bald-faced hornet nest houses a significant population. At its peak, usually in late summer, a colony can consist of anywhere from 100 to 400 workers. Some larger colonies have been recorded with up to 700 individuals.
Factors Affecting Population
Several factors influence population size. Abundant prey allows workers to feed more larvae, leading to larger adult populations. Weather conditions, such as temperature and humidity, also affect colony growth, with warmer and more humid environments often supporting larger populations. The queen’s health and productivity are important, as she lays all eggs for new colony members. The presence of predators or diseases can limit colony expansion by reducing the number of surviving individuals.
Colony Development Throughout the Season
The life cycle of a bald-faced hornet colony unfolds over a single season, beginning in the spring. A single fertilized queen emerges from hibernation and starts constructing a small nest, laying her first eggs. Initially, colony growth is slow as the queen raises the first generation of sterile female workers. These workers then take over nest enlargement, foraging for food, and caring for subsequent broods, allowing the queen to focus solely on egg-laying.
As the season progresses into late summer and early fall, the colony experiences rapid growth, reaching its peak population. During this period, the colony begins producing reproductive individuals, including new queens and males. After mating, the fertilized new queens seek sheltered locations to overwinter, while the rest of the colony, including the old queen and workers, naturally declines and dies with the onset of colder weather.
Nest Characteristics and Population
Bald-faced hornet nests appear as large, grey, papery structures. These nests are constructed from chewed wood fibers mixed with the hornets’ saliva, creating a durable paper-like material. Nest size correlates with the population density. Larger nests, often football or basketball-sized, indicate a more numerous colony. Within these structures, there are multiple tiers of hexagonal combs where eggs, larvae, and pupae develop.