Leafcutter bees

(Megachile spp.)



Leafcutter bees are solitary bees, native to woodland areas.

There are more then 140 species found in North America.

These grayish colored bees use their mouthpieces to cut pieces out of leaves to line their nests. Sometime they are very particular about which plant leaves they use.

The nests are made in wood cavities already present or in hollow plant stems.

Like most native bees, Leafcutters are very efficient pollinators.

They prefer legume blossoms (beans peas etc.), but are by no means limited to one plant’s nectar.

leafcutter bee

Some Quick Facts:

Leafcutters are native bees, important as pollinators.

Are not aggressive and have a mild sting that is used only when they are handled.

Leafcutters cut the leaves of plants. The cut leaf fragments are used to form nest cells.

Life and Habits:

Most common Leafcutter bees are roughly the size of the common honeybee, although they are somewhat darker with light bands on the abdomen. They also have different habits. Leafcutters are not aggressive and sting only when handled. Their sting is very mild, much less painful than that of honeybees or yellow jacket wasps.

Leafcutters are solitary bees, meaning that they don't produce colonies as do social insects (honeybees, bumblebees, yellow jackets, ants, etc.). Instead, individual females do all the work of rearing. This includes digging out nesting areas, creating nest cells and providing their young with food. Adult females may live up to two months and lay some 35 to 40 eggs during this time.

Leafcutter bees nest in soft, rotted wood; thick-stemmed, pithy plants, and in similar materials that the bees can easily cut through and excavate. Nest tunnels may extend several inches deep and coarse sawdust may be deposited at the entrance. This sometimes causes confusion with other wood nesting insects such as carpenter ants. However, Leafcutters restrict their tunneling to soft, rotted wood and do not cause damage to homes or other wooden structures.

These bees nest in soft, rotted wood or in the stems of large, pithy plants, such as roses.

Leafcutter bees are important native insects. They use cut leaf fragments to construct their nest cells. They often are essential pollinators of wild plants.

Leafcutter bee damage

Some Leafcutters are even semi domesticated to help produce alfalfa seed.

However, their habit of leaf cutting, as well as their nesting in soft wood or plant stems, often attracts attention and concern.

Leafcutter Bees pack the pollen into a thick mat of hair underneath

After the nest is made, the bees collect fragments of leaves to construct individual nest cells. The bees cut leaves in a distinctive manner, making a smooth semicircular cut about 3/4 inch in diameter from the edge of leaves.

Although they cut many types of leaves, Leafcutters prefer certain types, notably rose, green ash, lilac and Virginia creeper.

The injury to plants is often a minor curiosity. However, where Leafcutter bees are abundant and concentrate on cultivated plantings, the removal of leaf tissues can be damaging. Serious damage most often occurs in isolated rural plantings.

leafcutter bee nest

Leafcutters 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, very similar
to Orchard Mason Bees.

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.

Besides their value as pollinators, Leafcutter bees have created a new kind of beekeeper, the one who sells bee larvae to other growers in need of pollination services.

Unlike Mason Bees which are blue-black in color, Leafcutters are similar in size & color to honeybees, with stripes going across their abdomen in shades of black, grey and tan.

They do not collect pollen on their legs like honeybees but instead the females have stiff bristle type hairs on their abdomens designed to trap the pollen from the flowers they visit, coloring them yellow. The males do not have these hairs and his font feet are white.

Soon after mating the male bee dies, the female Leafcutter Bee lives for approximately 2 months to lay eggs. Like the Mason bee she will nest in pre-made bee houses with holes from 4"-8" deep and will make 12-15 cells, each cell lined with approximately 15 pieces of leaf with a loaf of "bee bread," a mixture of pollen and nectar placed in each cell, on which an egg is laid. They will make one cell per day on average.

Leafcutter bee

The larva will hatch after a few weeks and feed on the bee bread left for them. They will then turn into a pupa and depending on the species, and if eggs were laid early enough in Spring they will hatch a few weeks later. If the eggs are laid in late spring/early summer they will remain as a pupae through the remaining summer and winter until the following spring.

They will then pupate, chewing their way through the leaves and emerge as adults about 3 weeks later, the males which are in the front cells emerging first, followed by the females in the deeper parts of the nest. The cycle will then start again.

Native Leafcutter Bees are excellent pollinators of Alfalfa and one particular small species of bee was introduced accidentally into North America from Europe which does this job very well. These bees are used to pollinate crops of alfalfa, each single bee doing the job that would take many honeybees to do.

Leafcutter Bees also have the advantage that they do not seem to get the mite problems that the honeybee does and they do not have the painful sting like that of a wasp, hornet or honeybee.

Attract Leafcutter Bees and Other Pollinators

Orchard Mason Bees

Ground Bees

Squash Bees

Bumble Bees

Honey Bees

Protecting Pollinators

Pollination Primers

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