Leafcutter bees (Megachile spp.) are so named because the females cut pieces of leaves with their mandibles to line their nests. Mason bees, along with leafcutter bees, make up two main groups in the Megachilidae family. These bees are found throughout the world and are native to North America. They are often grayish in color and about the size of the European honey bee (Apis mellifera).

The alfalfa leafcutter bee (Megachile rotundata) is the most well-known pollinator in this group of bees. It is used commercially to pollinate alfalfa, carrot, onion, and blueberry crops. It also has potential as a pollinator of strawberry and melon crops, although it has not yet been used commercially with these crops. Other leafcutter bees also provide pollination services. Generally, leafcutter bees are important pollinators of wildflowers in the United States, particularly prairie wildflowers, and visit the larger flowers in the bean (Fabaceae) and aster (Asteraceae) families. Studies have shown leafcutter bee species pollinate peanut (Arachis hypogaea) crops and do so in the cool morning hours when this plant is most efficiently pollinated. Outside of the United States, several studies have looked at leafcutter bees as pollinators. In Egypt, Megachile flavipes pollinates Egyptian clover (Trifolium alexandrinium) a traditional forage crop in Egypt, and alfalfa. Megachile nigripes also pollinates Egyptian clover. In West Africa, leafcutter bee species are the most efficient pollinators of okra. Finally, leafcutter bee species are the most important pollinators of Vellozia leptopetala and V. epidendroides in Brazil. Both are members of the fibrous, shrubby plant family Velloziaceae.

References: Descriptions of Families, Sub-Families, and Tribes of Long-Tongued Bees, John Hilty, Insect Visitors of Illinois Wildflowers; Chapter 3: Clover and Some Relatives, S. E. McGregor In Insect Pollination of Cultivated Crop Plants, USDA, 1976; Leafcutting Bees, Megachilidae (Insecta: Hymenoptera: Megachilidae: Megachilinae), David Serrano, University of Florida, Institute of Food and Agricultural Sciences; Alfalfa and Clover Pollinators in Egypt, PollinatorParadise.com; Pollination increases protein content in Ocra, M.Sc. Moses T. Njoya, Institut fur Nutzpflanzenwissenschaften und Ressourcenschutz; Pollination of two species of Vellozia (Velloziaceae) from high-altitude quartzitic grasslands, Brazil, C. M. Jacobi and M. C. Laboissiere del Sarto, Acta Botanica Brasilica, Vol. 21, No. 2, Sao Paulo, Apr./June 2007; Chapter 1: Alfalfa, S. E. McGregor In Insect Pollination of Cultivated Crop Plants, USDA, 1976; Leafcutter Bees, W. S. Cranshaw, Colorado State University Extension; An Alternative to Honey Bees for Pollination, University of California Agricultural Experiment Station and Cooperative Extension Working for Californians.