Many people visualize bees living in large, communal hives, often high in trees or human-made structures. In reality, approximately 70% of bee species build their homes within the ground. These insects exhibit diverse nesting behaviors, challenging common perceptions about bees.
Who Nests in the Ground
Many bee species construct their nests underground, primarily living solitary lives. Mining bees (Andrena) are common ground-nesters, often appearing in early spring. They range from 5 to 17 millimeters, with females often larger and exhibiting pale hair bands. Mining bees are robust, densely haired, and possess specialized pollen-carrying structures on their hind legs.
Sweat bees (Halictidae family) are another group of ground-nesting bees, known for their attraction to human perspiration. Their size varies from 3 to 10 millimeters; many are black or brown, but some display metallic green, blue, or purple. While many sweat bee species are solitary, some can exhibit communal or semi-social behaviors.
Digger bees (Anthophora) are robust, fast-flying ground-nesters with velvety fur. They range in size from a honey bee to a bumble bee, with some displaying patterns or metallic hues. These bees are solitary, with each female creating and provisioning her own nest. Certain bumblebee species also nest underground, often utilizing abandoned rodent burrows or shallow cavities beneath objects like patio stones or dense grass.
Anatomy of a Ground Nest
Ground bee nests are excavated by female bees, appearing as small holes in the soil. These entrances may be surrounded by a small, volcano-shaped mound of excavated soil. The size of the entrance hole varies by bee species, from tiny for sweat bees to larger for bumblebees.
Beneath the surface, nests consist of a network of tunnels leading to individual cells. Female bees use their mandibles and forelegs to dig these tunnels, which can range from a few inches to several feet deep. Each cell is provisioned with “bee-bread” (a mixture of nectar and pollen) for developing larvae. Cells are lined with a waterproof secretion to protect the egg and larva; some species, like cellophane bees, use a cellophane-like material. Ground-nesting bees prefer well-drained, sandy or loamy soils, and select sunny, sparsely vegetated areas or gentle slopes for their nests.
Living Alongside Ground-Nesting Bees
Ground-nesting bees are non-aggressive and pose minimal threat to humans. Solitary species do not have a hive to defend and are unlikely to sting unless directly provoked or accidentally stepped on. Any sting is typically milder than that of other bee species. Male ground bees, while sometimes active around nesting sites, lack stingers entirely and are harmless.
These bees are valuable pollinators, playing a role in the reproduction of wild plants and agricultural crops. Their activity lasts only a few weeks in spring, after which they disappear until the following year. To coexist peacefully, leave their nesting areas undisturbed. Avoiding pesticides in these areas is important, and leaving patches of bare, well-drained soil can encourage their presence.