- Author: Kathy Keatley Garvey
Hello there, little leafcutter bee! Yes, you, foraging on the sky-blue Chinese Forget-Me-Nots!
You're just in time for National Pollinator Week!
Leafcutter bees, family Megachilidae, are so named because the females cut leaves and petals (perfectly round holes!) to line their nests. Smaller than honey bees--and much faster, leafcutter bees are easily recognizable by the black-white bands on their abdomen.
The females do all the work. They gather pollen and nectar, make the nests from the leaf and petal fragments, and lay eggs. They seal the egg chambers with the leaves or flower petals.
In our pollinator garden, leafcutter bees are quite fond of Chinese Forget-Me-Nots, Cynoglossum amabile. "Many wild bees prefer flowers in the violet-blue range—in part because these blossoms tend to produce high volumes of nectar," according to an Oct. 18, 2017 article in Science.org.
Of the 4000 bee species known in the United States, about 1600 reside in California. The leafcutter bee is just one of them. The family, Megachilidae, includes these leafcutting bees:Megachile angelarum, M. fidelis and M. montivaga; the alfalfa leafcutting bee, M. rotundata; the Mason bee, Osmia coloradensis; and the blue orchard bee (BOB), Osmia lignaria propinqua.
For more information on California's bees, read California Bees and Blooms: A Guide for Gardeners and Naturalists (Heyday), the work of UC-affiliated scientists,
Thorp, a global and legendary authority on bees and a distinguished emeritus professor of entomology at UC Davis, died June 7, 2019 at his home in Davis. He was 85.
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- Author: Kathy Keatley Garvey
Day 5 of National Pollinator Week: Meet the leafcutter bee, family Megachilidae.
It's a native pollinator, a solitary bee, and about the size of a honey bee.
Its coloration--the black-and-white banded abdomen--makes it easily recognizable.
As the name suggestions, they (the females) cut circular holes in leaves to line their nests for brood-rearing. Rosarians who enter their roses in competition aren't fond of them because of the "imperfections" in the leaves. A hole in one--or holes in many--aren't going to give them a whole lot of blue ribbons.
But having leafcutter bees in your garden is a joy. They're good pollinators and gentle bees. Leafcutter bees carry pollen on the underside of their abdomen, not on their hind legs like honey bees, do. Agriculturists manage the alfalfa leafcutter bee (Megachile rotundata) for crop pollination.
Leafcutter bees nest in natural cavities, mostly holes in soft wood or in hollow, pithy plant stems. You can also create bee condos or housing for them, drilling specific-sized holes in a block of wood.
We saw this little male Megachile foraging on Verbena. He paused for a few minutes and then took flight. Things to do and places to go...
