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Mason bees build mud walls in their nests

Without pollination, bounty from B.C. orchards and farms would drop dramatically

It's a Sunday afternoon in a Vancouver church hall, and Port Coquitlam beekeeper Pasquale Gnocato has something to show to 20 curious visitors. He produces a tray of several light brown, crusty bee cocoons, explaining that these have been hibernating in his refrigerator for months.

He cracks one cocoon open with his fingers like a peanut shell. Then, much to my surprise, what first looks like a house fly slowly emerges. It crawls about erratically, as if a bit dazed by its long sleep and by the light. Its shiny dark body, metallic blue hue, two sets of wings, and little white moustache (indicating a male) tells us that this is no fly, nor a honey bee, nor a wasp.

"Who wants to hold one?" asks Gnocato.

After several other visitors do the same, I put forth my hand too, yet a bit uncertainly, wondering if it might sting me. He places the bee on my palm, where it walks about unconcernedly for a while. Then it spreads its wings, alights, and flits merrily about the room, as though roaming for pollen in a pear orchard. This is the blue orchard mason bee, a very shy, solitary, and super effective pollinating bug that has become all the rage across the Lower Mainland, as garden stores are barely able to keep up with demand. Because this bee almost never stings, it is an ideal garden pet around children and animals, and the sight of their little wooden "condos" may soon become as familiar as birdhouses.

What is the character of the mason bee? How does it differ from other bees? In what ways can it benefit our environment? How can you set up a bee colony, even in apartments?

I f you are a backyard gardener in Canada, you may have noticed a drop in your fruit production. Over the past five years in many gardens, inadequate pollination is the cause. This is because wild honey bees have done the bulk of pollination, but two parasitic mites have decimated their colonies.

To the rescue comes the mason bee to help us grow more fruit and berries by carrying pollen grains from one place to another. They are so named for their masonry work, that is, building mud walls in their nests between cocoons. But they don't produce honey or beeswax, and Gnocato insists the masons will never replace the honey bee.

Without pollination, the bounty from B.C. orchards and farms would drop by hundreds of millions of dollars. Where the honey bee operates at less than 10 per cent efficiency in spreading pollen, mason bees do so at over 90 per cent, due to tiny hairs on their abdomen and a habit of digging into the middle of flowers. "Mason bees are solitary but gregarious, forming an aggregate community," says longtime Richmond beekeeper Brian Campbell. "There is no mason bee queen or worker bee, and there is never a threat of a mass defensive attack because they are not social at all."

The mason bee's great reluctance to sting helps explain their growing popularity, and makes them safe around children and pets. Even if you stand an inch away from a mason bee, stinging is the last thing they want to do because they are not protecting a hive, and are focused on collecting food and producing offspring. These bees will only sting if squeezed in a hand or stepped on. "It will only sting to protect its life, and who wouldn't?" says Gnocato. "I was stung several times on my hand, and you can feel it just like a mosquito bite, but within one minute the pain is nearly gone."

T he mason bee's lifecycle follows an eternal pattern. In spring, each female mason bee, working alone, flies to hundreds of plants per hour to carry pollen and nectar back to the nest. In the wild this is usually a long, narrow tunnel such as holes in trees bored by beetles, which is replicated well enough by wooden blocks with holes that are sold in garden stores.

The female goes to the back of the tunnel, lays one egg on a pile of pollen and then collects mud to build a wall, which doubles as the back of the next cell. Then she works to gather more mud and food for another cell, making a series of three-quarter inch long cells through the tunnel, so forming a mini-condo that Campbell calls "Vancouver's cheapest real estate."

The males are laid near the front exit, so in case of predator attacks-especially from woodpeckers-the males are sacrificed first, hopefully leaving the females to reproduce next year. (The male mason bees also visit flowers but only to get nectar for their own consumption.) Once a bee has finished with a nest, she plugs the entrance to the tunnel, and then might seek out another nest location.

When the egg hatches in about a week, the mason bee becomes a larva, and then a pupa, and feeds on the amassed pollen before it spins a cocoon. There it develops into adulthood in about a month, and then the bee hibernates through fall and winter. In spring as things warm up, the bees emerge from their cocoons, and those closest to the exit will eat through the mud walls, followed in turn by all the others. The males remain near the nests waiting for the females. When the females emerge, the first thing they do is mate, whereupon the males die.

Most of this species is found in places such as Canada where the temperature drops below 0° Celsius for long durations, although prolonged sub-freezing weather can kill hibernating bees. They can work in overcast weather, even drizzle, but not in heavy rain and wind. If the bees' housing faces southeast and warms up with morning sun, and is sheltered from the wind, they may start work earlier in the morning. In spring, warmer temperatures speed up the bees' emergence from their holes, yet one expert warns, "Some protection from the south facing sun is important, because in the summer, developing bees could overheat and die inside the nesting tunnel."

Mason bees nest in hollow stems, woodpecker drillings and insect holes. But a simple habitat made of wood drilled with holes will coax them into taking up residence in a backyard or on a balcony. You should place the bee houses in a warm dry place away from the wind, as near as possible to the area needing pollinating, and with a supply of mud, ideally rich soil dug out from one foot below ground.

Some people buy a beehouse of nontreated wood (chemicals can kill the bees) with three-eighths or 5/16-inch holes from a garden store, with a starter kit of cocoons. Others use reeds, or nesting trays, cardboard tubes, preferably not plastic.

By the end of October, beekeepers put mason bees into storage, and by early March return the bees outside. In fall, they extract the cocoons, take them from the holes, clean the holes, and store the bees in the fridge to protect them from predators such as pollen mites. During winter, the cocoons make a fine Christmas gift. Out of a 10 bee kit, six might be male, and of the four females, only one, two or none might produce a cocoon. The biggest mistake is not realizing that mason bees need fresh housing each year. Experts advise using hollow tubes made of heavy craft paper as liners to slide into the wooden holes. These can be pulled out (while being careful not to kill the unhatched bees or developing young in the process) and thrown out in case of pest infestation. Finally, the number of bees can double each year, and it's important not to get overeager and raise more bees than an area will support with pollen resources or that you can manage.

Patrick and Colleen Payne have more than 50,000 honey bees in their yard near Cambie Street, and for variety just bought 15 mason bee cocoons and a 36-hole bee house. "Most have emerged from their cocoons by now," he said, "and they sure have been buzzing around my plum tree and blueberry bushes."

Many experts say that, while apartment balconies aren't suited for honey bees, they can make fine homes for mason bees. Gnocato isn't so sure. Wind, variable temperatures and predator exposure increases beyond three meters high, he says. The balcony should not be higher than the fourth floor, because the bees don't like to fly more than 200 to 300 yards from home for food such as plants and maple or willow trees in a nearby yard. It is best to have a starter kit of 10 or 20 bees. Balcony bees had best be fed with a supply of spring flowering plants such as blossoms and roses. They also need a bucket of soil and water to make mud for their nests.

Marg Gordon, CEO of the B.C. Apartment Owners and Managers Association, says she hasn't yet heard any complaints about mason bees. "From the description, they probably can't be defined as pests because they do no damage and are benign toward humans," she wrote. Also, there are no civic or provincial laws on handling mason bees, unlike with honey bees.

T he mason bee business is booming, with at least a dozen outlets in the province selling bees. A set of bee housing supplies can range from $20 to $40. Garden stores sell bees in cocoons for $1.50 to $2 each, while Gnocato wholesales them for 75 cents, and the Environmental Youth Alliance for $1 (with the funds used to promote bee habitats). "Eventually, mason bee houses will be as familiar in yards as bird houses are now," Dr. Margeriet Dogterom told the Courier. The Coquitlam-based bee supplier has been working to spread the word about the bees for 12 years, is the author of a book on mason bee care, and has a blog at

Gnocato, who raises bees as a hobby, agrees. "Seven years ago I couldn't give away my cocoons. I made a big sign saying "Free Mason Bee Cocoons" and posted it on a telephone poll, and got almost no response. Now the demand is so great we run out of bees in about a month."

Yet this year is a little slower than usual, according to Brian Campbell: "Spring last year was miserable, so mason bees had a difficult time flying, finding food, mating, and so forth. This year, because of that, there is a bit of a shortage." Campbell, a certified beemaster and owner of Blessed Bee Farms (, runs urban "bee schools" on the East Side and in Dunbar, with eight week courses costing $250.

The Environmental Youth Alliance is one of the keenest promoters of mason bees. In 2009, in responses to huge losses in honeybee colonies, the members launched the Pollinators' Paradise Project ( html ), funded by Environment Canada and others. They set up 100 mason bee "condos" across the city and, teaming up with woodworking students from Van Tech and Britannia secondary schools, built big "super lodges" of bee cocoons bearing titles like the Fugong Wooden Temple and the Great Pyramid of Bee-za.

The Alliance also lectures on mason bees at many schools, runs a fourmonth apprenticeship program for youth to learn about beekeeping, and is doing a survey to map out the location of mason bees in Vancouver to eventually create an app. On June 24, Alliance members plan to dress up as bees to run in the Scotiabank half-marathon as a fundraiser for bee awareness. "Bees need us and we need them," said the Alliance's Hartley Rosen. "They're a vital part of our ecosystems' health and regeneration."

I n sum, the bee can provide a fascinating window into the cycles of nature. "The value of mason bees to human goes back thousands of years, because they are vital to our food supply," says Gnocato. "We need to educate and inspire more people to start their little colonies of this exceptional pollinator. Whether we do it for a hobby, a bumper crop, or to teach our children, we need more bees."