Rehn's Miner Bee

Andrena rehni, or Rehn's miner bee, is an oligolectic species of miner bee in the family Andrenidae. It is found in North America and was discovered by Henry Lorenz Viereck in 1907. The specific name honours James A. G. Rehn. Andrena rehni is a solitary, ground-nesting bee.

The species is associated with the American chestnut, which has become functionally extinct in its former distribution along the Appalachian Mountains due to the introduction of chestnut blight. As a result of the decline of the tree, Rehn's miner bee, which fed on its blossoms, has become increasingly rare. The reported range of Andrena rehni also overlapped with the range of the American chestnut; early entomologists noted that specimens were collected from flowering chestnut trees. The species had not been documented in nearly a century until it was rediscovered on an Allegheny chinkapin, a shrubby species related to the chestnut, in 2018 in Maryland by Sam Droege of the U.S. Geological Survey. Prior to the rediscovery of Andrena rehni, the American chestnut was believed to be wind-pollinated. Andrena rehni is now understood as a chestnut (including other species of the Castanea genus) pollen specialist; given the range of the American chestnut prior to the blight, it is probable that Andrena rehni was also widespread in the eastern United States.