 in isolated rural plantings.
Rose Leaf with Discs Cut from Edge by Leaf Cutting Bee.
Leafcutter bees do not eat the cut pieces of leaves that they remove. Instead, they carry them back to the nest and use them to fashion nest cells within the previously constructed tunnels. Then they provision each leaf-lined cell with a mixture of nectar and pollen. The female lays an egg and seals the cell, producing a finished nest cell that somewhat resembles a cigar butt. A series of closely packed cells are produced in sequence. A finished nest tunnel may contain a dozen or more cells forming a tube 4 to 8 inches long. The young bees develop and remain within the cells, emerging the next season.
There are a great many parasites that act as important natural enemies of leafcutter bees. As a result, leaf cutting activity may vary widely from year to year. Parasitic bees and wasps, velvet ants and certain blister beetles are among the most important enemies of leafcutter bees and other solitary bees.
Alfalfa Leafcutter Bee-Megachile rotundata. This is a European bee that has been introduced to other regions . As a solitary bee species, it does not build colonies or store honey, but is a very efficient pollinator of alfalfa, carrots and some other vegetables.
The importation of the species to North America was to assist in the pollination of food crops, and it has now widespread. The species is also found in Queensland, Australia, but not recorded in other states. The vernacular in Australia is Lucerne leafcutter bee.
Female alfalfa leafcutter bees have stingers, but both sexes will use their mandibles as a defensive mechanism, usually only defending themselves when squeezed or antagonized. Therefore bee suits, such as those required with honey bees, are not really necessary when dealing with these bees. The ratio of males to females is generally one to one.
Alfalfa Leaf Cutting Bee. Image Courtesy of USDA.
This species of leafcutter bee is cultivated to pollinate alfalfa grown for seed, a function that it does far more effici