Bees employ diverse strategies to survive colder months, a process known as “overwintering.” While “hibernation” is sometimes used, it doesn’t fully capture the varied methods different bee species use to endure low temperatures and scarce food. These survival methods vary significantly, reflecting the unique social structures and life cycles across bee types.
Honey Bee Overwintering
Honey bees (Apis mellifera) do not hibernate; they remain active within their hive throughout winter. When temperatures drop below approximately 50°F (10°C), worker bees form a tight cluster around their queen and any developing brood. This “winter cluster” acts as a collective heating unit, with bees on the outer layer packing tightly to provide insulation.
Bees inside the cluster generate heat by rapidly contracting their flight muscles without moving their wings, a process akin to shivering. This metabolic activity allows the colony to maintain a core temperature of around 92-97°F (33-36°C) within the cluster’s center, even when outside temperatures are freezing. The queen bee typically resides in this warm core, ensuring her survival. To fuel this continuous heat production, honey bees rely on the honey stores they collected during warmer months. A healthy honey bee colony needs approximately 80-100 pounds of honey to sustain itself through winter.
Bumblebee Hibernation
Bumblebees (Bombus species) employ a distinct winter survival strategy compared to honey bees. Unlike honey bee colonies, most of a bumblebee colony—including workers, males, and the old queen—perishes with the arrival of cold weather. Only newly mated queen bumblebees survive to establish new colonies the following spring. These queens seek sheltered locations to hibernate individually, a process more akin to true hibernation.
Common hibernation spots for queen bumblebees, known as hibernacula, include shallow burrows underground, under leaf litter, in rotten logs, or within wood piles. To prepare for this long dormant period, the queens gorge on nectar and pollen in autumn to build up fat reserves, which sustain them until spring.
Solitary Bee Overwintering
Solitary bees, which make up the vast majority of bee species, exhibit diverse overwintering methods. They do not form colonies or store large amounts of food. Adult solitary bees typically complete their life cycle and die before winter, with their survival depending on the next generation. Offspring usually spend the winter in an immature stage, such as larvae or pupae, protected within their natal nests.
These protected locations vary widely by species. Some solitary bees burrow into the ground, creating nests in sandy soil or clay. Others utilize hollow plant stems or tunnels in dead wood. Female solitary bees provision these nests with pollen and nectar for their developing young, sealing them to protect the future generation through the cold months.