Bumblebees are vital pollinators in both wild ecosystems and agricultural landscapes, crucial for the reproduction of many flowering plants, including various fruits and vegetables. These fuzzy insects are often wondered about regarding their nesting habits, particularly if they build homes underground. Understanding where bumblebees establish their colonies helps appreciate their ecological contributions and how to coexist with them.
Bumblebees and Ground Nests
Yes, many bumblebee species establish nests in the ground. They often use abandoned underground cavities, such as disused burrows created by rodents like mice or voles. These pre-existing tunnels provide a protected and insulated environment for the colony to develop. The queen, after emerging from hibernation, seeks out these sites, often drawn by the residual scent of the previous occupants.
Once a suitable burrow is found, the queen lines it with insulating materials like dry grass, moss, or animal fur to create a chamber for her eggs. The entrance to a ground nest can be subtle, appearing as a small hole in the soil or an opening hidden within dense grass. This insulation helps the colony maintain a stable temperature, important for the young’s development.
Beyond Ground Nests: Other Homes
While ground nesting is common, bumblebees are opportunistic and adapt to various other sheltered locations. Some species nest on the ground surface within thick vegetation, such as dense grass tussocks or under leaf litter. These surface nests benefit from the surrounding plant material’s insulation.
Bumblebees also nest in existing cavities within human-made structures or natural formations. This includes old bird nests, empty bird boxes, compost piles, wall cavities, or under sheds. Tree hollows and spaces beneath rocks are also potential nesting sites for some species, highlighting their adaptability in finding secure places to raise their young.
Spotting a Bumblebee Nest
Identifying a bumblebee nest often involves observing the bees’ characteristic flight patterns rather than spotting a visible structure. A key indicator is the consistent “traffic” of bees entering and exiting a specific opening, whether it’s a hole in the ground, a crevice in a wall, or an opening in a compost pile. Unlike honeybees, which may swarm, bumblebees typically fly purposefully to and from their nest.
Bumblebees are large, fuzzy insects, and their flight near the nest entrance is usually calm and direct, not erratic or aggressive. When a queen searches for a nest site in spring, she might fly in a slow, zig-zagging pattern, low to the ground, investigating potential openings. The nest itself, if visible, will not resemble the organized hexagonal comb of a honeybee hive but rather a more disorganized collection of wax cells and pollen lumps.
Living Alongside Bumblebees
Bumblebees are generally not aggressive and will only sting if they feel threatened or their nest is directly disturbed. Their primary focus is on foraging for pollen and nectar, and they typically ignore humans. If a nest is discovered, the best approach is to leave it undisturbed, as these colonies are annual and typically last only a few months, from spring through late summer.
Bumblebees do not cause structural damage to buildings because they do not excavate or chew wood; they simply use existing spaces. If a nest is in an inconvenient location, temporary adjustments like placing a barrier around the entrance can help keep pets and small children away. Relocation of a nest is complex and generally not recommended, as it can harm the colony; instead, it is advisable to contact a local bee expert for guidance if removal is absolutely necessary.