Digger bees, also known as ground bees, are common insects that nest in the soil of lawns and gardens. Their presence often raises questions about potential danger, leading many to misunderstand their nature. This article clarifies the characteristics and behavior of digger bees, emphasizing why they are generally not a threat to humans. Understanding these insects can foster a more harmonious coexistence.
Identifying Digger Bees
Digger bees are a diverse group, with over 70 species in the United States. They range from 1/4 to 1/2 inch long, similar to honey bees or bumble bees. Their appearance varies, often displaying dark, metallic, or striped bodies with markings of white, yellow, or reddish-brown. Female digger bees have noticeable hair on their hind legs for pollen collection. They are named for their distinctive ground nests. Their burrows appear as small, round holes in the soil, often surrounded by a small mound of excavated dirt, resembling a miniature volcano. Entrance holes are typically about the diameter of a number two pencil. They prefer dry, loose, or sandy soil, often in areas with sparse vegetation.
Understanding Their Behavior
Digger bees are solitary insects; each female constructs and provisions her own nest. Unlike social bees, they do not live in colonies with a queen or worker bees, nor do they defend a large hive. While they may nest in close proximity, creating the impression of a larger community, each nest remains independent. This solitary nature contributes to their non-aggressive temperament. Female digger bees possess a stinger but are reluctant to use it, stinging only if directly threatened, handled, or accidentally stepped on. Their sting is typically mild, often compared to a minor prick, ranking low on the Schmidt sting pain index. Male digger bees do not have stingers. Their primary activities involve foraging for nectar and pollen to provision their underground chambers for offspring.
Coexisting with Digger Bees
Digger bees play a beneficial role as important pollinators for various plants, including early-season crops and wildflowers. Allowing them to remain undisturbed contributes to the health and productivity of a garden. Since their presence is temporary, usually lasting a few weeks in spring, intervention is often unnecessary.
To encourage digger bees to relocate if nesting sites are a concern, several non-harmful methods can be employed. Increasing soil moisture through regular watering can make the ground less appealing for nesting, as they prefer dry conditions. Applying a thick layer of mulch or compost over bare soil can deter burrowing activity. Strong scents from plants like mint, eucalyptus, or citronella, or household items such as vinegar or cinnamon, may encourage them to move elsewhere. Professional pest control is rarely needed, but if considered, it should focus on non-lethal approaches that respect their ecological importance.