As colder weather arrives, wasps become noticeably absent. Their disappearance prompts curiosity about their whereabouts and how they survive the winter months.
The Winter Fate of a Wasp Colony
Most social wasp colonies do not survive the winter. As autumn progresses and temperatures fall, worker wasps, male drones, and the old queen all perish. Their decline is due to the scarcity of food sources, as plants and flowers die off, eliminating the nectar and insects they forage for. Worker wasps lack the necessary fat reserves and physiological adaptations to endure freezing temperatures and prolonged inactivity. By late autumn, nests built throughout the warmer months are abandoned and will not be reused.
The Queen’s Solitary Survival
While the rest of the colony succumbs to the cold, newly fertilized queen wasps are the sole survivors. These future founders of new colonies enter a specialized state of dormancy known as diapause, similar to hibernation. During diapause, the queen’s metabolic rate slows significantly, allowing her to conserve energy and subsist on stored fat reserves. Queens seek out sheltered, dry, and protected locations such as under loose tree bark, in attics, wall voids, sheds, garages, woodpiles, or building crevices.
The queen tucks her delicate wings and antennae to shield them from damage during her inactive state. To enhance survival in freezing conditions, she produces glycerol, a natural antifreeze compound, which circulates in her bloodstream to prevent ice crystals from forming within her cells. Although many queens enter diapause, their survival rates are low. Predation from insects like spiders poses a significant threat in their chosen overwintering spots. Unseasonably warm winters can also be detrimental, causing queens to emerge prematurely and face starvation due to a lack of available food.
Wasp Species and Winter Habits
While social wasps, such as common wasps, yellowjackets, and hornets, follow the colony-collapse and queen-hibernation pattern, solitary wasp species exhibit different winter survival strategies. These wasps do not form colonies or produce a caste system of workers and queens. Instead, many solitary wasps overwinter as larvae or pupae.
For instance, mud dauber wasps construct individual nests from mud or clay in sheltered locations. Their offspring develop through larval and pupal stages there, protected from the cold. Similarly, digger wasps create tunnels in the ground where their young remain in developmental stages throughout the winter. For many solitary species, adult wasps typically die off, and the next generation endures the cold season in a dormant, immature form within a protected cell.
Spring Awakening and Nest Building
As spring arrives and ambient temperatures consistently rise, typically reaching around 10°C, hibernating queen wasps awaken from their diapause. Their first priority upon emergence is to locate a source of nectar or other sugary liquids to replenish energy reserves after months of dormancy.
Following this crucial feeding period, each queen embarks on a solitary quest to find a suitable, sheltered location to establish a new nest. She constructs the initial, small nest, often about the size of a golf ball, using chewed wood fibers mixed with her saliva to create a papery pulp. Within these initial cells, she lays her first batch of eggs. Once these eggs hatch and develop into adult worker wasps, they assume the responsibilities of expanding the nest and foraging for food, allowing the queen to focus solely on laying more eggs and growing the new colony.