Leafcutter bees (Megachile spp.) are so named because the females cut pieces of leaves with their mandibles to line their nests. There are more than 140 species of leafcutter bees found in North America and many of them are native. They are often grayish in color and about the size of the European honey bee (Apis mellifera).

Unlike European honey bees, leafcutter bees are solitary bees. Solitary bees usually build and live in individual nests rather than in a hive or with a colony of bees, while social or communal bees do live colonially in hives or bee communities.

Mason bees, along with leafcutter bees, make up two main groups in the Megachilidae family. These bees are found throughout the world.