About 30 percent of U.S. crops rely on native bees for pollination, so it's important to know that we need many more pollinators than just honeybees. Megachilids and other native bees are often specialists that evolved alongside specific types of plants and are the only insects capable of pollinating them.
Megachilid bees pollinate wildflowers, fruits and vegetables, and a variety of other crops.
The plight of wild bees should concern us all. Fortunately, homeowners can easily help bee populations in their yards. Plant flowers that will bloom throughout the season, especially early and late in the season, when fewer pollen and nectar sources are available. Avoid pesticides and any plants or seed treated with neonicotinoids, which are harmful to all insects, including bees (look on plant or seed labels for imidacloprid or acetamiprid). Reduce mowing to allow broadleaf plants in your lawn to flower. Consider putting up a bee house.
Megachilid bees, being solitary, do not have a colony to defend the way social bees and wasps do, so they do not aggressively defend their nests. They only sting if mishandled. At any rate, the sting is said to be less painful than a honeybee's.
Some megachilids are bred commercially as pollinators, such as certain species of mason bees (Osmia spp.), which are especially helpful for pollinating blueberries, alfalfa, onions, carrots, and other fruits and nuts. Providing nesting holes for them, such as hollow plant stalks, drilled blocks of wood, and paper tubes, helps attract them.
On the down side, leafcutting bees are often attracted to landscaping plants such as roses, redbud, and other species with thin, flat, smooth leaves or flower petals. They may chew circles out of the leaves or petals, making them less attractive. We encourage you to tolerate this, because the bees are so beneficial as pollinators.
Several species have been introduced to North America to serve as additional pollinators in our country. One example is the alfalfa leafcutter bee (Megachile rotundata), a native of Europe.
The name is pronounced mega-KILL-id as well as mega-CHILL-id. It means "big-lipped," coming from Greek mégas (big) and kheîlos (lip). It refers to the large mouthparts these insects use in collecting materials for nest construction.