The buzz about mason bees

Photo by Will Dendis

It’s a beautiful spring day, and I’m surrounded by a swarm of bees. The last time I found myself in that position I was stung over 40 times. And that was just for reaching into an innocuous-looking bail of straw. Now I’m being told to knowingly plunge myself into the middle of the fray, urged to pick up one of a half-dozen wooden boxes dotted with holes full of bee eggs to get a closer look.

“They have never even looked like they might want to sting me,” Vivian Yess Wadlin told me earlier. “I’ve held them in my hand, they’ve landed on me.”

And the funny thing is, I believe her. I kneel down, watching as bee after bee makes her way onto the deck from a not-so-distant meadow, hovers for a few moments, orienting herself, and then enters one of a few dozen identical holes to deposit another cache of pollen, lay another egg, or construct a little mud wall. If my hand or camera comes between the bee and her hole, she bounces off and tries to get around it, treating me as an obstruction rather than an invader. Wadlin was right: these fuzzy little bees come in peace.


The males emerge first, in early April. They mill around, waiting for the females, who come from eggs buried deeper to ensure that any predator or pest first picks off the males. Wadlin says the males basically “jump” the females when they emerge. When all have hatched, the males make themselves scarce as the females begin working on nests for the next generation.

In each hole, they construct between four and six egg chambers, with each egg encased in pollen, and sealed off by the little mud walls that give the mason bee its name. They keep this up through May and early June. Then, their work done, the females die, too. (Depending on when you read this article, and how quickly you can get your hands on the necessary raw materials, there’s still time to attract some bees.)

Honeybees were introduced to theAmericasin the 1600s, and they’ve always been encouraged to prosper because of the delicious fruits of the labor and their propensity to multiply to numbers capable of pollinating vast fields of food crops — many of which, like the bees, were old-world imports. But over the last decade something has gone very wrong with the honeybee.

Vivian Wadlin and her mason bees

After years of study, scientists still don’t know what’s causing the worker bees in European honeybee hives to disappear. An as-yet undiscovered disease, stress, malnutrition, parasitic mites, a natural but previously unobserved cycle, cell-phone radiation and pesticides have all been suggested as possible causes for the bizarre phenomenon, which has led to a precipitous decline in the population of European honeybees throughout North America, Europe and Africa.

Beekeeper and self-described “bee doctor” Chris Harp of New Paltz said the winter die-off of honeybees was 70 percent inPennsylvaniaand 85 percent inMaryland(he didn’t have the numbers onNew York, but they’re not good news, either). “If you just take last year, we’ve got to be averaging 60 percent winter losses,” he said. “And that’s unsustainable in the long-term picture.”

And though conservationists are concerned for the long-term welfare of the species for its own sake, the decline of the honeybee matters to us for more selfish reasons, too. The insect is responsible for pollinating a third of our nation’s crops.

Harp believes the main causes of the problem are stress and malnutrition. There’s a whole industry devoted to moving beehives around from farm to farm.

Harp said that at this time of year you can see the rent-a-hives on pallets in local orchards. This practice places an unnatural stress on the GPS of an insect that evolved over millions of years to regard a single fixed hive as the home base.

Poor diet is the other issue. A single bee on a day’s mission will visit only one kind of plant, be it pumpkin, apple or almond. That’s the trait that makes honeybees so effective for farmers’ needs, but when surrounded by acres and acres of the same plant the result is an unbalanced diet, says Harp.

Farmers large and small could improve the situation in two ways: by leaving a portion of the land fallow to allow the bees to get a little variety in their pollen intake, and by raising bees on site.

While efforts to reverse colony collapse disorder continue, an important stopgap measure is to encourage the proliferation of so-called native bees. That’s where our friend Osmia lignaria — the mason bee — comes in. Pound for pound, a female mason bee can pollinate ten times as many plants as a honeybee, a consequence of their fuzzy bodies retaining more excess pollen as they go about their work.

That said, they can never replace the honeybee for agricultural uses. It’s a matter of biomass: each little mason bee house hosts 50 or so bees, while your average honeybee hive is home to 40,000.  “They are good pollinators, but they’re not mass pollinators,” said Harp. “There’s nobody that matches the honeybee’s capabilities in numbers.”

So while they could never replace the honeybee’s role on our farms, the mason bee can certainly help pick up some of the slack, says Harp. “Mason bees are a pollinator that will help in our current situation of not having enough pollinators,” he said.


Despite the female mason bee’s prodigious pollination capabilities, for the most part she’s labored in obscurity. Until now. Increasing numbers of environmentally conscious people who might never want to get involved in the potentially prickly practice of beekeeping have taken to drilling a few holes in untreated blocks of wood, setting them on the porch, and watching as scores of harmless mason bees magically hone in on these ideal nesting sites and get to work.

Wadlin, ofHighland, is one of those people. After reading a short article in Audubon magazine that sung the mason bee’s praises and provided instructions on creating a mason bee box, she decided to give it a try. She told her son, a teacher in the Wallkill school district, about the idea, and he ended up having his class build a number of boxes for a science project, with extras going to her and to others interested in the idea.


The boxes are quite simple: anyone with a drill and a saw could make one. Get a block of untreated softwood (pine or fir will work), 6 1/2″ by 6 1/2″ or 6 1/2″ by 4″, and about a foot long, and mark on one face nine rows of five holes each, about an inch apart. Using a 5/16″ bit, drill holes about six inches deep (mark your bit at the six-inch mark to avoid drilling through to the other side).

Audubon recommends placing a fence post cap on the top to prevent moisture from building up in the holes, and you can order specially built mason-bee houses on various websites. But that’s probably not essential. In fact, one website suggested drilling holes in an old log. That makes sense. In nature, “They live in any holes,” says Wadlin.

Before I see the bees in action, Wadlin tells me, “They’re really cute. You’re going to want some.”

She’s right. It’s easy to see how someone could read an article about the mason bee’s utility and buy a few boxes, only to fall in love with them. “I started three years ago,” said Wadlin. “This is my third group, and now I can’t wait for them to hatch so that I can watch them.”

She describes the pleasures of bee-watching on her porch, which happens to have a magnificent view of theHudson. “I am sitting here surrounded by all these little bees that are intent on doing what nature intended them to do,” she said. “And no matter how hard the wind blows, they still turn, face into it, and find their hole, go in and lay they eggs or whatever they’re doing in there. They’re just absolutely fascinating to watch.”

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