Ground bees are a diverse collection of insect species that share one common trait: they construct their nests by burrowing into the earth. These native pollinators are often misunderstood and mistaken for more aggressive insects like yellow jackets, which also nest underground but belong to the wasp family. The common name “ground bee” encompasses a variety of species, including Mining Bees (Andrenidae), Digger Bees (Anthophora), and many Sweat Bees (Halictidae, all of which play a significant role in local ecosystems.
Identification and Solitary Nature
A defining feature of most ground bees is their solitary life cycle, which distinguishes them from social insects like honeybees and hornets. Each female ground bee works independently, excavating a separate burrow and provisioning it with pollen and nectar for her offspring without the help of a colony or worker caste. Approximately 70% of all bee species worldwide are solitary, with the majority of these being ground-nesters.
The nests are typically visible as small, volcano-like mounds of fine soil surrounding a central entrance hole. Although they are solitary, females often build individual nests in close proximity, forming dense aggregations in areas with exposed, well-drained soil and sparse vegetation. These bees are active for only a few weeks in the spring or early summer, focusing on the brief period required to mate and provision their nests before disappearing until the next year.
Essential Role in Pollination
Ground bees are highly effective pollinators, making a substantial contribution to both natural and agricultural environments. Their solitary nature enhances foraging efficiency because they do not have a hive to return to for pollen storage. Many species carry dry, loose pollen on specialized hairs on their bodies or abdomens, which transfers easily between the flowers they visit, promoting cross-pollination.
These bees are particularly valuable because they often emerge earlier in the spring than honeybees, providing pollination services for early-blooming plants like fruit trees and shrubs. Many ground bees are also “specialist” pollinators, meaning they have co-evolved to collect pollen from only a specific genus or family of native plants. This specialization is important for the reproduction of native flora that might otherwise be ignored by generalist species.
Understanding Stinging Behavior
The primary concern for most people encountering ground bees is the risk of being stung, but their solitary life cycle makes them docile. Unlike social bees, ground bees do not have a large colony, honey stores, or a queen to protect, which eliminates the primary motivation for aggressive defensive behavior. A female ground bee generally reserves her sting for a situation where she is physically crushed or aggressively handled.
Male ground bees lack a stinger entirely. While females possess a stinger, stings are rare and often occur only if a person accidentally steps directly on a bee or traps it against their skin. This reluctance to sting contrasts sharply with social insects like yellow jackets, which aggressively defend their large, interconnected nests.
Strategies for Coexistence and Management
Ground bees are temporary visitors, with their activity period lasting only about four to six weeks in the spring. Since they are beneficial pollinators and not destructive to lawns or gardens, the best approach for homeowners is to simply leave them undisturbed during their brief nesting period. If a nesting area is located in a high-traffic spot, the bees will naturally disappear once their reproductive cycle is complete.
For those who need to discourage nesting in a specific area, simple, non-chemical environmental modifications can be effective. Ground bees prefer dry, bare, or sparsely vegetated soil, so increasing the moisture content of the soil through frequent, heavy watering will make the area less appealing for nest construction. Covering the bare soil with a dense layer of mulch or overseeding thin turf areas to create a thick, continuous carpet of grass also deters burrowing. These steps eliminate the preferred nesting habitat without resorting to harmful chemical treatments, which are generally ineffective against solitary nests.