A bee hotel, often called a solitary bee nesting site, is a structure designed to support native pollinator populations. These installations provide artificial nesting cavities for solitary bee species, which do not live in colonies like honeybees. By mimicking natural shelter, bee hotels offer a straightforward way to contribute to local biodiversity and provide a safe location for egg-laying and larval development.
The Purpose and Design of Solitary Bee Shelters
The purpose of a bee shelter is to replicate the small tunnels that solitary bees seek out in nature, such as hollow plant stems or old beetle burrows. Construction consists of tubes or drilled holes with a closed back end. This dead-end design is essential to shield developing larvae from predators and parasites.
Effective shelters utilize materials like untreated wood blocks, bamboo, or sturdy cardboard tubes. The interior surfaces must be smooth and free of splinters, as rough edges can damage the delicate wings of adult bees. Tunnels should have a diameter ranging from 3/32 to 3/8 inches (2 to 10 millimeters) to accommodate different bee species.
The depth of the nesting tunnels is a specific requirement for successful reproduction. Smaller-diameter holes should be 3 to 4 inches deep, while larger-diameter holes should extend 5 to 6 inches. This depth ensures the female bee can lay a mixed ratio of male and female eggs, preventing the production of only male offspring.
Understanding the Occupants: Who Uses a Bee Hotel?
Bee hotels are built exclusively for solitary, cavity-nesting bees, such as Mason bees (Osmia spp.) and Leafcutter bees (Megachile spp.). Solitary bees lack a hive and a worker caste, meaning every female is fertile and responsible for building her own nest. These bees are generally non-aggressive because they have no large colony or stored honey to defend.
The female bee initiates nesting by filling the back of the tunnel with a mixture of pollen and nectar, known as a pollen loaf. She lays a single egg on this food source and seals it off with a partition, creating an individual cell. Mason bees typically use mud for partitions, while Leafcutter bees use meticulously cut pieces of leaves.
She repeats this process, creating a linear series of cells within the tunnel, each containing one egg and its own food supply. Once the tunnel is filled, the female seals the entrance with a final plug and moves on to start a new nest. The larvae hatch, consume the pollen loaf, and develop inside their protected cell, often emerging the following spring.
Optimal Placement and Seasonal Maintenance
Optimal placement maximizes sun exposure and stability for the developing brood. The shelter should face South or Southeast to capture the morning sun, which warms the tubes and aids bee activity. It must be mounted securely to a sturdy surface, such as a fence or wall, to prevent movement that could disturb the fragile cells inside.
The hotel should be positioned at least three feet off the ground, typically four to five feet high, to protect it from dampness and ground-based predators. After the bees seal their nests in late summer, maintenance is required to ensure the health of the next generation. Over time, nesting materials can accumulate parasites, such as pollen mites, and diseases like Chalkbrood fungus.
To prevent the spread of pathogens, the nesting materials should be replaced or cleaned annually or biennially. A common method is to use removable paper or cardboard inserts inside the tunnels, which are harvested in the late fall or winter. These occupied tubes are stored in a cool, dry, and protected environment until the following spring, when the emerging adults are released near new, clean nesting materials.