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U.S. Forest Service

Miner Bee (Anthophora abrupta)

By Kelly Rourke, Pollinator Partnership

Miner bees, also known as chimney bees, are smaller than a honey bee, with a stout, furry body. They are often mistaken for bumble bees, also being black and yellow summertime bees. They are friendly, non-aggressive and typically do not sting or bite. Despite their small stature, mining bees are very important to flower pollination, especially in the mid-west region of the United States. Anthophora abrupta’s geographic distribution ranges from Texas to Florida, stretching up the East Coast to Canada.

Miner bees are most well-known and studied due to their complex nesting behavior. Miner bees are solitary, ground nesting bees that like to establish their home in well-drained soils, like clay, present in banks, hills, and road cut-outs. They have also been found burrowing between stones of old buildings and between logs in cabins or barns. Most commonly, female bees dig a tunnel in the soil using loose earth to construct a chimney-like turret, which represents a single nest. Nests are often clustered together in close quarters but females only provide for their own nest and future offspring with no overlap in generation. Miner bees have been known to nest in the same location for many years.

After mating and establishing their nests, A. abrupta females line the tunnel walls with a glandular secretion which turns to a solid waxy plate. This process waterproofs a cup-like cell for the provisioning of the eggs. A single egg is laid in each cell and floats on a pollen mixture foraged by the females for about five days before hatching. The larvae proceed to consume the pollen substance and cell lining over the following three weeks. The offspring overwinter in the prepupae stage, and come April, they shed their skin and two weeks later emerge from their burrows as adults.

The head, legs and abdomen of A. abrupta are lightly coated in brown-black hairs while the thorax is covered in dense, pale yellow-orange hairs. The wings are nearly transparent to slightly cloudy with brown-black veins.

Anthophora abruptaAnthophora abrupta. Henryetta, Okmulgee County, Oklahoma, USA 2006. Photo by Charles Schurch Lewallen.

Anthophora abrupta Small bees (Anthophora abrupta) making homes in a large root ball upended in August of 2008 by Hurricane Gustav. Baton Rouge - BREC Bluebonnet Swamp Nature Center, East Baton Rouge Parish, Louisiana, USA. May 14, 2009. Copyright © 2009 John Hartgerink.

The adult females are 14.5 to 17 millimeters long and the adult males are 12 to 17 millimeters long. The males have a distinctive set of hairs on the margin of their clypeus (the area on the center of the face between the eyes and mouth), like a mustache. The males carry pheromones attractive to females in their mustaches. The female’s cheeks are approximately the same width as their eyes and they have a strongly protuberant clypeus. Both male and female A. abrupta forage for their own nectar, which makes this species a very effective pollinator.

Anthophora abrupta Male Anthophora abrupta. Prince George’s County, Maryland, 2014. Photo by Sam Droege.

A. abrupta has been recorded to visit many flowers and is considered a forage-plant generalist. It collects pollen from a wide range of wildflowers native to woodlands and prairies. This includes visits to the rare, Mead’s milkweed (Asclepias meadii), along with Rhododendron, Oenothera, Penstemon, Rubus, Asclepias, Cornus, Delphinium, Iris, Monarda, Nepeta, Rosa, Diospyros, Melilotus, Trifolium, and Pastinaca species. Anthophora abrupta are potential pollinators of many important crops including cranberry, tomato, blackberry, asparagus, persimmon, clover and raspberry. However, pollinator management techniques have not been established for this species.

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