Leaf-cutter bees (belonging to the large genus Megachile) build linear nests in any suitable hollows using pieces of soft, thin leaves. They cut circular or oval pieces from leaves with their mandibles and curl them between their legs for the flight back to the nest. While nest sites are frequently existing holes above ground, some species excavate shallow burrows in soil.
Many other species of Megachile chew the leaf-tissue into a paste or scrape resin from plant stems and use these materials to build their cells in borer holes in dead wood or any other suitable holes they can locate.