The life cycle of social wasps, such as yellow jackets and hornets, is structured around the seasons. Most of the colony dies off completely in the winter. This yearly cycle ensures the old nest is abandoned, and only the newly fertilized queens survive the cold months. These surviving queens carry the genetic lineage of the colony into the next year.
The Annual Cycle and Colony Breakdown
The wasp colony’s demise begins in late summer when the nest reaches its peak size, often containing thousands of sterile female workers. The old queen shifts her focus to producing the next generation of reproductives: fertile males and new queens (gynes). These new reproductive members leave the nest to mate, signifying the end of the colony’s purpose.
Once the new queens and males are produced, the original queen stops laying worker eggs, and the social structure rapidly collapses. The worker wasps previously relied on larvae for a sugary substance in exchange for protein, leaving them without their primary carbohydrate source. With no young to feed or queen pheromones to maintain order, workers scavenge for sugar outside the nest, leading to the increased aggression seen in autumn.
As temperatures consistently drop and the first hard frost arrives, the remaining workers and the old queen die. They perish from a combination of cold and starvation, lacking the physiological adaptations needed to endure winter. Unlike the new queens, workers do not enter dormancy, and the empty paper nest is not reused and begins to deteriorate.
The Overwintering Queen
Survival through winter depends entirely on the newly mated queens, which enter physiological dormancy known as diapause. This regulated process is distinct from the true hibernation of mammals. Queens prepare by building substantial fat reserves in specialized tissues called fat bodies. These reserves serve as their sole energy source for the entire winter.
Before the cold sets in, the fertilized queen seeks a sheltered location that provides insulation and protection from predators. Common overwintering sites include dry spaces under loose tree bark, within rotting logs, soil crevices, or inside human structures like wall voids and attics. The queen is entirely alone during this period, and her metabolic rate slows dramatically to conserve stored fat.
The queens possess adaptations for surviving the cold, including producing cryoprotectants like glycerol, which acts as a natural antifreeze. This chemical prevents ice crystals from forming within her cells, allowing her to endure sub-freezing temperatures without tissue damage. She remains in this dormant state until spring conditions trigger her awakening. Many queens do not survive the winter due to desiccation, predation, or exhausting their fat reserves.
The Return of the Wasp
The queen’s diapause ends when a sustained increase in ambient temperatures, typically above 10 degrees Celsius (50 degrees Fahrenheit), rouses her. The warming weather signals the return of available resources, prompting her to emerge and begin the next annual cycle. Her immediate action is to forage for nectar and sap to replenish energy and scout for a suitable new nesting location.
This period marks the founding phase of the new colony, where the queen performs all initial labor alone. She finds a sheltered site and uses chewed wood pulp mixed with saliva to construct a small, golf ball-sized nest containing the first few cells. She lays the first batch of eggs, which she must single-handedly feed and defend until they mature into the first generation of sterile worker wasps. Once these first workers emerge, they take over foraging, nest expansion, and brood-rearing duties, allowing the queen to focus exclusively on laying eggs.