The seasonal appearance of social wasps, such as yellow jackets and hornets, follows a precise biological cycle dictated by temperature. Their entire life span is completed within a single warm season. Activity begins with the emergence of a lone queen in the spring and ends with the death of the entire colony in the autumn, making their presence dependent on the annual change in climate.
Spring: The Queen’s Emergence
The first wasps to become active are the new queens, who spent the winter in a state of dormancy. They shelter in protected locations like hollow logs, attics, or under tree bark. Their emergence is triggered by rising temperatures, typically when sustained daytime warmth reaches above 50°F to 60°F.
Once she emerges, the queen immediately begins foraging for a nesting site and materials to construct a small, initial nest. She chews wood fibers and mixes them with saliva to create a paper-like structure, often no larger than a golf ball. The queen then lays her first clutch of eggs, which she tends to and feeds herself, acting as the founder and first worker of the new colony.
Summer: Sustained Colony Growth
The colony enters a period of rapid expansion after the queen’s first offspring mature into sterile female workers, usually four to five weeks after emergence. These workers immediately take over all duties, including foraging, nest expansion, and caring for subsequent larvae. This allows the queen to focus solely on laying eggs, rapidly increasing the colony’s size.
During this mid-season phase, workers are driven to feed the developing larvae, which require a high-protein diet. Adult wasps forage for protein sources, such as insects, spiders, and carrion, which they feed to the young. In exchange for this nourishment, the larvae secrete a sugar-rich liquid that the adult workers consume for energy.
Late Season: Peak Activity and Decline
The perception of wasps as nuisances spikes in the late season, from late August through September, as the colony’s life cycle begins its final stage. By this time, the nest has reached its maximum population, often housing thousands of individuals. The queen transitions her egg-laying focus from producing sterile workers to creating the next generation of reproductive males and new queens.
Once these new reproductive wasps emerge and leave the nest, the queen stops laying eggs, resulting in a decline of protein-hungry larvae. This loss means worker wasps are cut off from their primary source of liquid sugar, which they received by feeding the young. The vast population of adult workers must then find an external source of simple carbohydrates to maintain their energy. This need for sugar drives the existing population to scavenge for easy sources like fallen fruit, sugary drinks, and human food at outdoor gatherings.
Winter: Dormancy and Survival
As temperatures drop and the first hard frosts arrive, the annual cycle concludes. The original queen, the remaining worker wasps, and the male wasps all perish, as they cannot survive the sustained cold. The nest, constructed from paper pulp, is abandoned and will not be reused in the following season due to the risk of disease and parasites.
Only the newly emerged, fertilized queens survive the winter. They seek protected crevices in tree bark, wall voids, or under debris to enter a state of metabolic slowdown called diapause. This solitary hibernation preserves them until the spring thaw, allowing them to emerge and found entirely new colonies when the weather warms again.