Megachilidae: Carder Bees (Anthidium spp.)

Biology

Carder bees are so-named because they ‘card’ or comb cottony down from hairy leaves using it to construct brood cells. There are 23 species in North America with at least one species, Anthidium maculosum, in the Pacific Northwest. A European species, Anthidium manicatum, was accidentally introduced into North America in the early 1960s and it is now widespread in the US, including Washington State. This is the Anthidium species, most likely to be seen in Washington home gardens. Anthidium manicatum is robust-bodied, about the size of a honey bee and brightly patterned in yellow and black, similar to a yellowjacket wasp. It nests in existing cavities like cracks in walls or knot holes in wood. Nest cells are formed that use hairs shaved from pubescent leaves of plants like Mullein. Cells are provisioned with pollen and nectar. Wool carder bees are fast fliers, and capable of hovering. Males are aggressive, defending territories from other bees.