Mining Bee

Andrena vaga — the gray-backed mining bee — is one of about 1,500 species in genus Andrena (the mining bees — one of the most ecologically important groups of wild pollinator bees on Earth) and one of the most distinctive European species. Andrena is the largest single bee genus by species count and is found across all of North America, Europe, Asia, and Africa. Andrena vaga is widespread across temperate Europe in early spring (March-April). Adults are 12-15 mm long, females larger than males. Females have a striking color pattern: BLACK ABDOMEN combined with DENSE GRAY-WHITE FUR ON THE THORAX (the source of the 'gray-backed' common name). Mining bees (genus Andrena) are SOLITARY GROUND-NESTING BEES — each female excavates her own underground burrow in sandy or loose soil and provisions the burrow with pollen-and-nectar provisions for her own offspring. Unlike honey bees, bumblebees, and other social bees, mining bees do not form colonies, do not have workers, and do not have queens — every adult female is independently reproductive. Despite the solitary biology, many mining bee species form COMMUNAL NESTING AGGREGATIONS on suitable habitat — south-facing sandy slopes that provide warm soil for nest excavation and brood development. Andrena vaga is one of the most spectacular aggregation-forming species: SINGLE AGGREGATIONS CAN CONTAIN 10,000-50,000 INDIVIDUAL FEMALE NEST BURROWS, all closely-spaced in a few square meters of sandy soil. The aggregations are visible as dense networks of small holes in sandy ground (each hole the entrance to one female's nest burrow), with fast-moving female bees flying in-and-out throughout the spring foraging period. Andrena vaga is an OBLIGATE WILLOW POLLEN SPECIALIST — females collect ONLY pollen from willow (Salix) flowers for larval provisioning. The willow specialization restricts the species to areas where willows grow and constrains the foraging biology to early spring (when willows bloom). The species is essential for early-spring pollination of willows across Europe and is one of the most important wild pollinators of European riverbank, wetland, and other willow-dominated habitats. Mining bees as a group (genus Andrena) are essential WILD POLLINATORS for many crop plants (apples, pears, blueberries, almonds, and other early-spring blooming crops) and for native wildflowers across all temperate regions of the world. The species is harmless to humans (mining bees are non-aggressive, rarely sting, and the sting is medically insignificant) and is one of the most-photographed solitary bees in European spring nature photography because of the dramatic nesting aggregations.