Hornets, like many social insects in temperate climates, operate on a strictly seasonal cycle. Visible and highly active throughout the warmer months, the large colony structures suddenly appear to vanish with the first sustained cold temperatures of the year. This annual disappearance is not a migration or deep sleep, but rather a catastrophic end for the vast majority of the colony’s inhabitants. The life cycle is seasonal, tied to the availability of food and mild weather.
The Annual Colony Dissolution
The transition from late summer to winter marks the programmed collapse of the hornet colony. As the season progresses, the original queen shifts her egg production to yield a final generation of individuals: reproductive males, known as drones, and new, future queens, often called gynes. These new reproductives leave the parent nest to mate with individuals from other colonies, ensuring genetic diversity before the cold sets in.
With the onset of freezing temperatures, all existing workers and the founding queen rapidly perish. Hornets are unable to regulate their body temperature, and their paper nests offer insufficient insulation to withstand prolonged cold. This die-off is total, dissolving the active social unit and leaving the nest completely uninhabited.
Survival Through Diapause
Survival rests entirely on the newly fertilized queens, which undergo a physiological state known as diapause. This deep, hormonally-induced dormancy allows the queen to persist through the winter months. Before entering this state, the young queens spend time in the nest accumulating large fat reserves, which serve as their sole energy source until spring.
Once mated, the queen leaves the deteriorating nest to find a secure overwintering site. She seeks out a small, protected space called a hibernaculum, which often includes sheltered areas like loose soil, crevices in rotting logs, under tree bark, or within the voids of man-made structures. The queen’s metabolism slows drastically. Her body produces a high concentration of glycerol, which acts as an antifreeze to prevent her bodily fluids from freezing in sub-zero temperatures. She remains inactive and alone until rising spring temperatures signal her to emerge and begin a new colony.
The Fate of the Abandoned Nest
The large, intricately constructed paper nest is an annual structure that is never reused by hornets in the following year. Once the new queens have dispersed for diapause, the nest serves no further purpose and is left to be reclaimed by the environment. The primary reasons for abandonment include the risk of parasites and pathogens that may have accumulated over the season, and the overall degradation of the paper material.
The material of the nest, which is a blend of chewed wood fibers and hornet saliva, is not durable enough to withstand an entire winter season intact. Exposure to rain, snow, and wind causes the paper carton to weaken and disintegrate, especially in exposed locations. Although the physical structure of the old nest may persist through the winter, it offers no viable shelter for the newly emerging queens. They are programmed to start fresh by building a new structure in a location that offers optimal conditions for the next season.