Scopa

Definition

Most solitary bees carry pollen dry, packed into a brush of stiff branched hairs. In mason bees, leafcutters and wool carders that brush is on the underside of the abdomen, which gives a foraging female a distinctive yellow belly and is unmistakable once known. The mechanical consequence matters: dry scopal pollen sheds readily in flight, so scopa-carrying bees deposit far more pollen per visit than a honey bee carrying a wetted, packed corbicular pellet — which is why a few hundred mason bees can pollinate an orchard acre as effectively as a full honey bee colony.

Where the word gets used loosely

Absence of a scopa does not mean the insect is not a bee. Cleptoparasitic bees have none because they gather no pollen, and Hylaeus carries pollen internally in the crop. Both are genuine bees that fail the usual visual test.

Bee records that discuss this

• Yellow-faced beesThe bees that look least like bees. Yellow-faced bees are small, black, effectively hairless and marked with pale yellow or white on the face, and almost everyone who sees one assumes it is a small wasp. They carry pollen internally, swallowed into the crop and regurgitated at the nest, which means they have no pollen brushes at all — the feature people use to recognise a bee is simply absent. Seven Hawaiian species were the first bees anywhere to be protected under the United States Endangered Species Act.