The majority of bees are solitary insects that use the soil for nesting and reproduction, rather than living in large, communal hives. Ground-nesting bees represent an estimated 70% of all bee species globally. They are common in yards and gardens, particularly in areas with bare or sparsely vegetated soil, though their unique nesting behavior often leads to misunderstanding.
Who Are the Ground-Nesting Bees
The group of bees that burrows in the ground is diverse, consisting of several prominent families, including Mining Bees, Digger Bees, and Sweat Bees. Mining bees (family Andrenidae) are typically small to moderate in size, measuring between 5 and 17 millimeters long. They often appear dark-colored and slightly fuzzy, emerging primarily in the early spring months. Females use specialized, dense hairs, called scopae, on their hind legs to collect and transport pollen back to their subterranean nests.
Digger bees (tribe Anthophorini) are often larger and more robust than mining bees, with some species reaching up to 3 centimeters in length. These bees are fast-flying and possess a hairy body, and males in particular may exhibit pale yellow or white markings on their faces. Sweat bees (family Halictidae) are highly recognizable for their small size, usually ranging from 3 to 10 millimeters, and for the striking metallic colors found in many species, such as brilliant green, blue, or purple. These common native bees get their name from their attraction to the salts in human perspiration.
Solitary Life Underground
Ground-nesting bees are defined by their solitary life structure, a key difference from the social hierarchy of honey bees and bumble bees. Each nest is the work of a single female, who is responsible for construction, provisioning, and egg-laying without the help of a worker caste or queen. She excavates a main tunnel that descends into the soil, which then branches out into several side tunnels.
At the end of each side tunnel, the female constructs a single brood cell, which she meticulously provisions with a ball of pollen and nectar for her future offspring. She then lays one egg on top of this food source, seals the cell, and repeats the process until the nest is full. The appearance of these nests on the surface is a distinct, small mound of excavated dirt, often described as volcano-shaped with a pencil-sized hole in the center. While these nests are separate and individually managed, the bees may nest in dense clusters or aggregations if they find a patch of soil that meets their specific requirements. The larvae will feed on the provisions, develop, and typically overwinter underground, only to emerge as adults the following spring.
Understanding Their Temperament
Ground-nesting bee behavior is characterized by a docile temperament, which stems directly from their solitary nature. Unlike social bees, these insects do not have a large, collective hive to protect, so they lack the aggressive, defensive instincts seen in honey bees or yellow jackets. The female will only sting if she feels physically threatened, such as when she is accidentally stepped on or handled.
The majority of bees seen hovering near the nest entrances are often the males, who patrol the area looking for emerging females to mate with. Although these males may fly quickly and appear territorial, they are harmless because they do not possess a stinger. The female, who is generally focused on digging and provisioning, rarely initiates conflict. This non-aggressive behavior means that ground bees pose very little threat to people or pets, even when nests are clustered together.
Living Alongside Ground Bees
Ground-nesting bees are beneficial insects that contribute significantly to the local ecosystem as effective native pollinators. Their short period of activity, typically lasting only a few weeks in the spring, means their presence is temporary. The small mounds of soil they create also aerate the lawn, and the nests collapse and disappear naturally after the bees emerge.
If their nesting activity is occurring in a high-traffic area, simple, non-lethal methods can encourage them to relocate without causing harm. These bees prefer dry, bare, or sandy soil, so changing the soil conditions makes the area less appealing. Consistently watering the affected area for several days makes the soil moist and unsuitable for nesting, prompting the bees to move elsewhere. Alternatively, covering bare patches of soil with a thick layer of mulch or establishing dense turfgrass through seeding will physically block the bees’ access to the ground.