Ground bees are a common type of solitary bee found in many regions, nesting in soil. Often mistaken for more aggressive stinging insects, ground bees are generally harmless. Accurate identification, based on their distinct visual characteristics and nesting habits, helps appreciate their role as pollinators.
Key Physical Characteristics
Ground bees generally range from half an inch to three-quarters of an inch long, often similar to or slightly larger than honeybees. Their bodies are typically cylindrical and appear less robust than the rounder bumblebees. Some species exhibit a metallic sheen in shades of green, blue, copper, or reddish-brown, while others are black, brown, or dull yellow, sometimes with light banding.
Most ground bees have a hairy body, especially on their thorax and legs, aiding in pollen collection. Unlike honeybees or bumblebees that have specialized pollen baskets, ground bees collect pollen on general body hairs. Their antennae feature a distinct elbow-like joint and are segmented, with females typically having 12 segments and males 13. Ground bees also have two pairs of transparent wings.
Recognizing Their Ground Nests
Ground bees are recognized by their distinctive nesting sites in the soil. These nests are typically marked by small, volcano-shaped mounds of excavated dirt, known as tumuli, that surround the entrance hole. The entrance holes are usually small, about 1/4 inch in diameter.
Ground bees prefer to build their nests in bare patches of soil, sparsely vegetated lawns, garden beds, and along sidewalks, especially in sunny, well-drained areas. Each female ground bee digs her own solitary tunnel. While many bees may nest in close proximity, creating the appearance of a larger colony, each burrow remains independent.
Distinguishing Them From Other Insects
Several visual and behavioral cues help differentiate ground bees from other ground-nesting insects. Yellow jackets are typically brighter yellow and black with smoother, less hairy bodies and a narrower waist. Yellow jackets are social insects living in large colonies. Their nests, often hidden underground, show continuous, high-volume activity from a single, unadorned entrance, which is larger than a ground bee’s hole.
Bumblebees are larger and more robust and fuzzy than ground bees, with dense hair covering their abdomens. They are social bees that typically nest in existing ground cavities, such as abandoned rodent burrows or dense grass, rather than excavating fresh holes with visible soil mounds. Unlike ground bees, bumblebees possess specialized pollen baskets on their hind legs.
Cicada killers are significantly larger than ground bees, measuring 1.5 to 2 inches long. They are characterized by their black bodies with distinct yellow bands and reddish, transparent wings. Their burrow entrances are also much larger, about 0.59 inches wide and often accompanied by a U-shaped mound of excavated soil with a trench through it, contrasting with the smaller, volcano-shaped mounds of ground bees.