At some point in time you have probably seen a bee hotel at your favorite garden center. They usually have bundles of bamboo inserted into a structure. Most of them are brightly painted and whimsical in appearance. North America is home to around 4,000 bees. Most of them nest in the ground but around 1,200 are considered tunnel nesters. Tunnel nesting bees, also called cavity nesting bees, will seek out cracks or crevices to construct a nest. They are solitary in nature but often you’ll find multiple queens working in the same area because the location is favorable. Bee hotels are a great way to invite these insects into your landscape.
One size doesn’t fit all
Most commercially made hotels only offer one size diameter hole for bees to choose from. The University of Nebraska-Lincoln recommends that holes for tunnel nesting bees should range from 2.4 mm (3/32”) up to 12.7 mm (½ inch) to accommodate the diversity of the different sizes of bees. Another fault of some commercial bee hotels is their tunnels are open at both ends. Tunnel nesting bees need to feel secure before they construct their nest. There should only be one entry point into the nesting tunnels.
Another common mistake is the depth of the tunnels. When drilling into blocks of wood the larger the tunnel the deeper it should be. According to the Xerces Society larger holes should be 13-15 cm (5” to 6”) deep. Smaller holes should only be 8-13 cm (3” to 5”) deep. Take care not to drill through the wood when creating the tunnels. The Xerces Society also recommends that holes should be about 19 mm (3/4”) from center to center and the tunnel should be about the same distance from the edge of the block of wood.
While most commercially made bee hotels are a quick and easy way to get started they might not be properly constructed. Before buying make sure that the hotel meets all the qualification to attract tunnel nesting bees to your garden.
“Creating a Solitary Bee Hotel” E. Bauer et. al
“Attracting Native Pollinators” Xerces Society