Bring on the Bees
By building this simple nest box, you can attract a gentle but prolific pollinator to your suburban yard and enjoy the fruits of its labor.
By Kris Wetherbee
With its classic yellow abdominal stripes and signature buzz, the honeybee might be the quintessential pollinator. But it's a lesser-known member of the Megachilidae family that is the ultimate ally to the fruit trees, berry bushes, and spring flowers in your garden. The orchard mason bee is such a prodigious pollinator that it would take as many as 10 honeybees to match one female's productivity.
Think of this mild-mannered North American native, with its blue overcoat and transparent wings, as an apiarian mail carrier, working on cold or rainy days that keep nonnative honeybees in their hives. Unlike its better-known counterpart, the orchard mason bee—also known as the orchard bee, mason bee, blue orchard bee, or blue bee—does not produce honey, a food supply that sustains a honeybee hive through the winter. Rather a female must participate in a weeks-long, life-and-death race to collect a supply of nectar and pollen to nourish the next generation of unborn bees, while simultaneously drinking nectar to sustain herself.
A wood dweller like the carpenter and hornfaced bee, the female orchard mason bee lays her eggs in holes not much bigger than the diameter of her body. She deposits the eggs one at a time and includes a pollen ball moistened with nectar for each one. She then seals off each chamber with a thin layer of mud (hence the name mason).
When she reaches the end of the tunnel, she caps it off with a plug of mud. After 3 to 10 days, depending on the ambient temperature, the eggs hatch, and the larvae devour the pollen balls. Then they spin cocoons and enter a pupal stage. In midsummer the bees transform into adults, though they stay inside the cocoons until the following spring, when the next generation of bees emerge to find their own nest holes. Males leave the nest first and die within a few days of mating, but females continue to forage and lay eggs for an additional four to six weeks.
As suburban sprawl reduces the number of natural cavities created by tree borers and woodpeckers throughout the orchard mason bee's range—which includes most of the country—manmade nesting blocks can supplement the bee's habitat.
Mason bees will take up residence in a simulated abode made from a simple pre-drilled block of wood (follow the instructions below). February is the best time to create this new habitat, since female adults can begin laying eggs in March, depending on your region's weather.
Although orchard mason bees are excellent pollinators for most fruit trees and plants, they will also visit a wide variety of other early spring-blooming trees and shrubs, such as hollies, willows, and redbuds, as well as such garden favorites as azaleas. It's easy to entice them to your yard—just make a beeline to your local lumber store.
BLUEPRINT: MASON BEE NESTING BLOCK
Mounting the Nesting Block
Be sure to set out your nesting block in February, so it's in place before early spring flowers bloom. To keep your block from swaying in the wind, it's best to attach it firmly to a tree trunk or fence post, or under the eaves or on the side of a building. It should be three to six feet off the ground. Place the block in a protected location with the holes facing southeast or east, so the bees receive sun in the morning. Set out a plastic container with mud and water nearby so the females will have what they need to construct egg-cell partitions. If your hibernating bees are going to spend the winter outdoors, be sure to place them in a spot that's protected from rain, snow, and wind. Otherwise, you can bring bee blocks inside in the fall to overwinter in a refrigerator or any other location where the temperature will remain at a constant 35 to 40 degrees Fahrenheit.
To learn more about other Audubon at Home projects, log on to www.audubon.org. and go to Audubon At Home.
Oregon writer and gardener Kris Wetherbee is the author of Attracting Birds, Butterflies & Other Winged Wonders to Your Backyard (Sterling Publishing, 2005).
© 2006 National Audubon Society
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