Megachilidae

In Minnesota, the family Megachilidae includes fourteen bee genera: Anthidiellum, Anthidium, Ashmeadiella, Chelostoma, Coelioxys, Dianthidium, Heriades, Hoplitis, Megachile, Osmia, Paranthidium, Pseudoanthidium, Stelis, and Trachusa. Two of these genera—Coelioxys and Stelis—are cleptoparasitic (cuckoo) bees with hosts that include other bee genera in the family Megachilidae. Females in this family (other than the cuckoo bees) share a common trait: They carry pollen on hairs on the underside of their abdomen. This trait is unique to the family Megachilidae; nest-building bees in the remaining five families in Minnesota (and North America) carry pollen on their hind legs (or internally as is the case for Hylaeus). In addition to the scopal (pollen-collecting) hairs on the underside of the abdomen, Megachilidae also have two forewing submarginal cells and large mandibles often used for collection or manipulation of the supplemental nesting materials.

Megachilidae nest in a variety of sites; a majority of species nest aboveground in a pre-existing or excavated cavity, and a minority belowground, often in shallow burrows. This family includes many bee genera that source nesting materials to line and cap their nest, or create free form nests. The materials a given species may source include: mud, wood fiber or fragments, plant hairs, plant resin, leaves, and pebbles. The plants used to source these nesting materials are a critical habitat component for each bee species. Lastly, this family includes many pollen-collecting specialists (oligolectic bees).