Leafcutter Bee, Leafcutting Bee, Plug Bug

Order Hymenoptera, family Megachilidae, several species

Adult--1/4" to 3/4"

Leafcutter bee.  Photos from Colorado State University  Cooperative Extension

Leafcutter bee injury.

Adults are stout-bodied and dark brown to black, sometimes with yellow or beige markings. Wings are clear or smoky. They range in size from about as large as honey bees to about half as large. Large heads and highly polished black or metallic blue or green bodies. Sometimes bands of white hairs across the abdomen.

Solitary insect that uses pieces of leaves to line its nests in cavities in the ground, dead wood, hollow stems, snail shells, pipes, and other openings. Leafcutters use their mandibles to cut neat circles or partial circles out of the edges of leaves plant material for their nests. You've probably seen this damage on your rose foliage. Complete metamorphosis.

Many plants, but especially roses, hollies, and fruit trees. They are common everywhere.

Pollen and nectar from many flowers.

Important plant pollinators and should not be killed. Troublesome around machine shops because they will plug up any exposed pipes. Mechanics have learned to tape over the ends of pipes, fuel lines, and other openings.

Natural control: Good biodiversity will keep them from being too abundant. Birds, praying mantids, and lizards.

Organic control: None needed in most cases--their damage is only cosmetic.

Mason bees are very closely kin. They are metallic blue or green in color. Osmia spp. are short metallic-colored pollinators that nest in the ground or in natural cavities. Mason bees will also seek a cavity in wood, soil, masonry, pithy stems of plants, keyholes, and snail shells. They line the holes with cement made of clay, sand, and a sticky secretion from their mouths instead of using leaves, as the leafcutting bee does. In either case, eggs are placed in each cell with a mass of pollen, nectar, or honey.

Leafcutter bee nesting on porch, with sawdust.    Photos from Colorado State University Cooperative Extension

Cells of leaf-cutter bee, packed with    pollen, exposed from a hollow stemmed weed.