Leafcutter bees
Megachile spp.
Genus-level entry for the solitary leafcutter bees, named for the way females snip smooth semicircular pieces from leaves and petals to line and seal their brood cells. They are cavity nesters, using hollow stems, beetle borings in dead wood, and similar pencil-sized tunnels, which makes them ready users of stem habitat and bee hotels. As largely polylectic (generalist) foragers, they carry pollen on a dense brush of hairs on the underside of the abdomen rather than on the legs, and are productive pollinators of summer legumes and composites in the garden. The neat crescent notches they leave on rose, redbud, ash, and lilac leaves are cosmetic damage to the plant, not a health problem.
Conservation
There is no genus-wide formal listing, and many of the roughly 240 leafcutter bee species native to North America are not individually assessed. A NatureServe conservation review found that a substantial share of native North American Megachile species may face conservation concern, while the widely managed alfalfa leafcutter bee (Megachile rotundata) is an introduced Eurasian species and is not considered threatened. Treat the genus as a mix of secure, data-deficient, and at-risk species rather than assigning a single status.