The bald-faced hornet (Dolichovespula maculata) is a large species of aerial yellowjacket wasp, not a true hornet of the genus Vespa. It is known for its distinctive black and white coloration and the large, exposed paper nests it constructs high above the ground. Understanding the typical foraging patterns of this social insect is important for determining the colony’s location and safely navigating areas where workers aggressively defend the nest.
Identifying the Bald-Faced Hornet and Its Nest
The bald-faced hornet is readily identified by its black body and prominent ivory-white markings, particularly on its face and the tip of its abdomen. Workers typically measure around three-quarters of an inch in length, making them the largest species in their genus. They are frequently mistaken for true hornets due to their size and aggressive nest defense.
Their colony is housed within a large, gray, paper structure called a carton nest. These football-shaped nests are constructed by chewing wood fibers mixed with saliva. They are commonly found suspended high in tree branches, shrubs, or sometimes under the eaves of buildings, and a mature nest can exceed two feet in length.
Factors Determining Foraging Radius
The maximum distance a bald-faced hornet can travel is significantly greater than its typical foraging radius. Although individuals may fly up to a mile or two if resources are scarce, the effective working range is much shorter. Workers generally maintain an efficient foraging range of about 100 yards (300 feet) from the colony, minimizing energy expenditure relative to nutritional gain.
The foraging radius is highly dynamic, expanding or contracting based on external factors. A primary influence is the availability and density of suitable prey and nectar sources in the immediate area; if food is plentiful nearby, workers venture less far.
Colony size also plays a significant role in determining the travel range. Larger colonies, which require substantially more protein and sugar, necessitate a wider foraging area to meet the needs of the growing brood. Environmental conditions like temperature, wind, and rain can also limit the distance of foraging flights, keeping workers closer to the nest.
The Purpose of Traveling
The travel of worker hornets is driven by three distinct resource demands necessary for colony survival and growth.
Protein for Larvae
Protein is collected primarily through prey capture to feed the developing larvae. Workers are effective predators, hunting and subduing soft-bodied insects like flies, spiders, and caterpillars. They chew this prey and bring it back to the nest as a high-protein paste, ensuring the next generation has the building blocks for growth.
Carbohydrates for Adults
Adult hornets rely on carbohydrates for their own flight energy and sustain themselves by foraging for sugars. This involves collecting nectar from flowers, consuming tree sap, or feeding on the juices of ripe or rotting fruit.
Cellulose for Nest Construction
Workers must gather cellulose for nest expansion. They use their powerful mandibles to scrape wood fibers, often targeting weathered lumber like unpainted fences or dead wood. These fibers are mixed with saliva to create the lightweight, durable paper pulp material used to expand the gray carton.
Seasonal Peaks in Activity
The intensity and range of travel are heavily influenced by the colony’s annual life cycle. In the spring, a single overwintered queen initiates the nest and forages alone to rear the first generation of sterile female workers. She constructs a small, initial nest and feeds the first brood until they emerge.
As the first workers emerge, they assume the duties of foraging and nest expansion, allowing the queen to focus solely on egg production. The population size increases exponentially throughout the summer, reaching its maximum worker count by late August or early September. This peak population corresponds with the greatest resource demand and the widest potential foraging radius.
Activity ceases abruptly with the first hard frost of the season, which kills all remaining workers and the founding queen. Only the newly mated queens survive, seeking sheltered locations to hibernate until the following spring.