Bumblebees do construct nests to raise their young, but the structure and lifestyle of their colonies differ significantly from the perennial hives of their honeybee relatives. Bumblebee nests are small, temporary homes that are active for only a single season, and their internal appearance is often described as disorganized or messy. The queen bee is responsible for initiating the nest, gathering materials, and raising the first brood of workers entirely on her own. This solitary beginning leads to a modest-sized colony that focuses on the production of new queens before the season ends.
The Annual Life Cycle of a Colony
The life of a bumblebee colony is dictated by the changing seasons in temperate climates. A single, mated queen emerges from winter hibernation, often from loose soil or leaf litter, to begin the cycle in the spring. She spends a few weeks foraging to build her strength before searching for a suitable nesting site. Once the nest is established, the queen provisions it with food and lays her first batch of eggs, which she incubates and cares for alone.
These first offspring develop into female worker bees, which take over foraging, nest maintenance, and caring for subsequent broods. As the summer progresses, the colony grows, peaking in size from 50 to around 400 individuals, depending on the species. By late summer or early fall, the queen produces unfertilized eggs that become males, and fertilized eggs that develop into new queens. These new reproductives leave the nest to mate. As the weather cools, the original queen, the workers, and the males all die, leaving only the newly mated queens to hibernate and restart the cycle the following spring.
Where Bumblebees Choose to Build
Bumblebees are opportunistic nesters, preferring to use existing cavities rather than excavating large structures themselves. The queen searches for dry, sheltered, and well-insulated spaces to protect the brood from temperature fluctuations. A common choice is an abandoned burrow made by a small mammal like a mouse or vole, which provides a ready-made underground tunnel and chamber lined with insulating materials.
The nests can also be found in a variety of other protected locations. Above-ground sites include:
- Dense clumps of grass
- Old birdhouses
- Compost heaps
- Under garden sheds
- Within wall cavities and insulation
The queen investigates prospective holes or crevices by flying in a low, zig-zag pattern, using both sight and smell. Since the colony only stores a few days’ worth of food, the nest does not need to be located close to large flower patches, as the bees can travel over half a mile to forage.
Internal Structure of the Nest
The inside of a bumblebee nest differs structurally from the organized, hexagonal comb found in a honeybee hive. The queen creates a small, rounded chamber and lines it with materials like moss, dry grass, or animal hair for insulation. Within this chamber, she constructs small, thimble-shaped wax cups, or “wax pots,” used for storing nectar.
The brood is reared in a cluster of wax cells that lack the uniform symmetry of honeybee comb, appearing as a lumpy, untidy pile. The queen lays her eggs on top of a clump of pollen and then seals the cluster with wax. As the larvae grow, they spin silk cocoons, and the adults chew their way out. These empty cocoons are repurposed by workers as storage vessels for nectar or pollen, contributing to the nest’s disheveled appearance.
How to Identify a Nest and Coexist
Identifying a bumblebee nest involves observing a steady stream of bees flying in and out of a hidden entrance. The bees are recognizable by their round, fuzzy bodies, distinguishing them from the sleek, less hairy appearance of most wasps and hornets. If a nest is found, it is recommended to leave it undisturbed because bumblebees are non-aggressive and will only sting if the nest is physically threatened or handled.
Unlike yellowjackets, which are highly defensive, bumblebees are focused on foraging and do not swarm. The entire colony dies off by the end of the season, meaning any inconvenience is temporary. If a nest is in a high-traffic area, simple measures like placing a temporary barrier, such as an upturned wire basket, can redirect foot traffic and allow the bees safe passage until the colony finishes its annual cycle.