The Ashy Mining Bee (Andrena cineraria) is a common, solitary insect that appears early in the spring season, often observed in gardens and parks. The sight of these bees digging holes and appearing in large numbers can raise concerns about potential stinging and danger. This article examines the behavior and biology of the Ashy Mining Bee to clarify the actual safety risk this widespread pollinator poses to humans and pets.
The Stinging Risk
Only the female Ashy Mining Bee possesses a stinger; the male cannot sting. Even the female is highly unlikely to sting because these solitary insects do not defend a large communal hive or stored honey reserves. Their temperament is generally docile and non-aggressive toward humans.
A sting typically occurs only if the bee is accidentally trapped, crushed, or aggressively handled. For many solitary bees, the stinger is often too short to effectively penetrate human skin. When a sting does occur, the sensation is usually very mild, often compared to a minor pinprick.
The discomfort from an Ashy Mining Bee sting is generally minimal and short-lived, rated low on the Schmidt Sting Pain Index. The pain lasts only a few minutes and is significantly less intense than the sting from a honeybee or a wasp. The Ashy Mining Bee does not pose a substantial danger, and the health risk is low unless an individual has a severe allergy to insect venom.
Identifying Ashy Mining Bees and Their Behavior
Identifying the Ashy Mining Bee is straightforward due to its striking, almost monochrome appearance. The bee is similar in size to a common honeybee. The female has a glossy, hairless black abdomen and two prominent bands of light gray or white hair across her thorax. The male is generally smaller, with gray hair that is more spread out.
These bees are among the earliest to emerge, typically flying from March through June, and are frequently seen foraging on early spring flowers. Their behavior is defined by their solitary nature. Each female digs her own individual nest tunnel, a process that gives the insect its “mining” name.
The nest is a simple, vertical burrow, extending 10 to 20 centimeters deep into the soil. As the female excavates the tunnel, she pushes the soil out, creating a small, distinctive “volcano-like” mound of earth at the entrance. After mating, the female provisions individual nest cells with pollen and nectar before laying a single egg in each.
Coexisting with Solitary Ground Nests
When conditions are optimal, several female Ashy Mining Bees may choose to build their individual nests in close proximity, creating a nesting aggregation. This clustering is not a communal hive; each bee remains responsible only for her own burrow and offspring. This lack of a shared nest to defend is the primary reason for their non-aggressive disposition.
The appearance of dozens of small volcano mounds can be alarming, but this activity is temporary, lasting only for the few weeks the adult bees are active. The bees’ digging behavior is beneficial to the soil, helping with aeration and drainage. After the adults die, the larvae remain underground, developing until they emerge the following spring, and the soil mounds soon disappear.
To promote safe coexistence during their brief season, individuals can mark off the area where the nesting aggregation is present. The most effective management strategy is avoiding direct disturbance to the ground nests and refraining from walking barefoot in the immediate vicinity. Attempting to remove or exterminate these temporary nests is unnecessary and detrimental to local pollination efforts.