Are Leafcutter Bees Making Holes in Your Leaves?

Most common leafcutter bees, Megachile sp., are the same size as honey bees. However, leafcutter bees are mostly black in color with light colored bands across their abdomens. Also, female leafcutter bees carry pollen on stiff hairs on the underside of the abdomens rather than on the sides of the hind legs like honey bees. Leafcutter bees tend to be non-aggressive and usually only sting when handled.
Leafcutter bees are solitary bees, so individual female bees dig out nesting areas, create nest cells and provide young with food. Adult females cut circular or elongate pieces of leaves from such plants as roses, azaleas, bougainvilleas, redbuds, and other cultivated and wild plants. They use the leaves to construct walls and partitions for nesting cells. These nests can be found in such places as hollow twigs, holes in buildings, and in the ground. The nesting cells are provided with nectar and pollen collected from flowers. One egg is laid in each nesting cell. When the egg hatches, a white, legless, grub-like larva emerges and develops within the cell. The larva then pupates before emerging as an adult out of the cell the next season.
Leafcutter bees are important pollinators of plants. However, they can cause damage to plants when large populations exist on smaller, developing plants.

Control Options:
There are many natural enemies of leafcutter bees such as parasitic bees and wasps, velvet ants and some blister beetles. The use of insecticides is usually ineffective for the prevention of leaf cutting. One control option is to cover susceptible plants with cheesecloth or other loose netting during periods when leafcutter bees are most active. Also, leafcutter bee populations can be reduced if breeding sites are eliminated so such items as rotting boards or thick stemmed plants with hollowed openings should be removed from the landscape.

A leafcutting bee, Megachile sp. (Hymenoptera: Megachilidae), adult. Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.