Hornets, which are social insects belonging to the genus Vespa, operate on an annual cycle tied to the changing seasons in temperate climates. Like most social wasps, hornets do not reuse their nests from previous years. The entire colony structure is designed for a single season of growth and reproduction, meaning a new nest must be established every spring.
The Hornet Annual Life Cycle
The annual life cycle of the colony, driven by temperature fluctuations, explains why nests are not reused. The cycle begins in the spring when a single, fertilized queen emerges from hibernation, usually around March or April. This founding female, or foundress, immediately begins constructing a small starter nest from wood fibers chewed into a paper-like pulp.
The queen lays her first batch of eggs, nurturing the larvae until they develop into sterile female worker hornets. Once the first workers emerge in late spring or early summer, they take over foraging and expanding the nest structure. This allows the queen to focus solely on laying eggs. The colony population grows rapidly throughout the summer, reaching its peak size by late summer or early fall.
As autumn approaches, the queen produces a final brood of new reproductive individuals: fertile males and new queens. The new queens mate with the males, who die shortly afterward, and then seek sheltered locations to hibernate for the winter. Common hibernation spots include hollow logs, leaf litter, or wall voids. With the arrival of the first hard frost, the original queen, the workers, and the males all die, leaving the nest abandoned.
What Happens to Abandoned Nests
Once the colony dies off in the fall, the physical structure of the nest remains, posing no danger of re-infestation. The abandoned nest is composed of paper carton, a material created from chewed wood fiber mixed with hornet saliva. Although durable, this structure is not built to withstand the long-term effects of weathering.
Throughout the winter, the nest is subjected to rain, snow, and wind, causing the papery layers to decompose and decay. The structure gradually breaks down and often disintegrates, especially if exposed to the elements. Nests in dry, sheltered areas may persist for a longer time. Since hornets do not reuse the old nest, it will not attract a new colony the following year. However, the presence of an old nest suggests the location has environmental conditions that might still appeal to a new queen. Homeowners can safely remove an abandoned nest after the first few hard freezes ensure the colony is dead.
How New Hornet Nests Are Established
The process of establishing a new nest begins when the newly fertilized queens emerge from their overwintering sites in the spring. They immediately search for a suitable, dry location that offers protection from predators and the weather. Common nesting sites include sheltered areas like tree hollows, under eaves, wall cavities, sheds, and attics.
The queen selects a site based on factors like proximity to building materials, which are typically weathered wood, and a stable anchor point for the initial structure. She collects wood fibers, chewing them into a pulp to create the first few cells of the new comb. This small, umbrella-shaped structure is the foundation of the new colony. The queen will labor alone until her first brood of workers matures enough to take over the construction duties. Homeowners can deter new queens by sealing cracks or gaps in the building structure and ensuring attic and shed vents are properly screened before the spring season begins.