Mason bees built to resist colony collapse
Native pollinators easier to care for and not affected by varroa mites

John Schmitz
For the Capital Press

Can a tiny insect sometimes mistaken for a common housefly help liberate U.S. agriculture from colony collapse disorder?

A Seattle-area beekeeper thinks so.

"If they don't find out what this colony collapse disorder is all about, they're going to have to look for alternatives to the honeybees for pollination," said Steve Brustkern, who has been propagating orchard mason bees for 10 years.

"For pollination purposes, mason bees are easier to care for and do a more effective job," he said. What's more, they don't seem to be affected by CCD.

Orchard mason bees, which are native to the Western U.S. and Canada, offer several advantages over honeybees, Brustkern said.

For one thing, they don't have a stinger. And no stinger means no need for protective gear and smokers when working with the bees. But the biggest difference is that mason bees, when going head to head with honeybees, are superior pollinators, Brustkern said.

"Because they pollinate 40 to 70 times more effectively than honeybees, we only need 350 to 500 per acre to pollinate crops."

Mason bees will also work at lower temperatures than honeybees, Brustkern said.

Unlike honeybees, no queen rules over orchard mason bees, which are essentially solitary in nature. Instead, each female worker bee, after mating with several males, will lay her own eggs. After each egg is laid and stocked with pollen and nectar, the brood cell is closed off with a little mud wall constructed by the female, thus the name "mason" bee.

Once the egg transforms to the larval stage, it forms a protective cocoon. Inside the cocoon the developing bee progresses to the pupa stage before becoming an adult. During hatching, the young adult chews its way out of the cocoon.

Unlike queen honeybees, female mason bees give birth only once a year, laying around 30 eggs in the process. Hatchings can be delayed or speeded up by controlling the temperature.

"If you want to extend the season, what you do is put out the amount that is required (for early blooming crops) and hold some back in the refrigerator (for, say, later-maturing cherries), keeping them asleep or dormant," Brustkern said. With mason bees, only eggs that are destined to become workers are fertilized. As is the case with drone honeybees, the only reason for the male mason bees' existence is mating.

Prior to humans propagating mason bees, the bees nested in pre-existing holes, such as those found in wood, shingles and the bark of trees. "They very rarely make their own nests," Brustkern said.

Today, orchard bees are reared and live in small man-made nesting tubes.

Brustkern runs around 30,000 orchard mason bees, 20,000 of those near Bakersfield, Calif., waiting for almond pollinations in early spring. The remainder are kept in Seattle.

While mason bees are not susceptible to the same deadly varroa mites that attack honeybees, they do have their own unique enemies, such as mites.

"One of the things I do to fight the mites is open up the (brood) tubes and clean the cocoons with a combination of tepid water and a little bit of bleach," Brustkern said.

Mason beekeepers also move their bees less than honeybee keepers, a tactic that is believed to lessen mite impacts, Brustkern said.

As for mason bee rental fees, "With the honeybees going south, they're now getting upwards of 80 cents a bee," Brustkern said. "Once people factor in the fewer number of bees needed vs. what the cost of a honeybee hive is, which is $175 and up now, the orchard mason bee has become more and more desirable."

So why aren't more growers using them? "We're not sure," Brustkern said. "Our thought has been that obviously there's been some reluctance on the part of large cash crop growers, the biggest one being almonds. It's such a make-or-break deal that so far almond growers have been willing to pay whatever it costs to get (honeybee) hives in."

One financial shortcoming that mason bees have when compared with honeybees is that they don't produce honey, which oftentimes can mean the difference between profit and loss for beekeeping operations. All nectar collected is either used to feed developing bees or to nourish adults.

Interest in mason beekeeping is growing, Brustkern said. "I'm getting calls all the time from folks that either want to do it or want to learn more about it, and see what the applications would be on a commercial basis."
Pluses and minuses
"There's definitely a future for them," UC-Davis extension apiculturist Eric Mussen said of orchard mason bees. "There's no doubt in my mind."

But just how effective the little solitary insects can be in huge monocultures, such as almonds and apples, is another story.

Mussen agreed that orchard mason bees, as well as other insects, are superior pollinators when compared with honeybees. But, he added, "The reason honeybees get the job done is that we can put so many of them out there that they keep revisiting and revisiting (flowers)."

While mason bees aren't "vexed" with the same parasites and diseases that attack honeybees, they do have their own problems, Mussen said.

One of those, it appears, is a susceptibility to certain products related to fungicide treatments.

One huge attribute mason bees possess that makes them so attractive is that so far they have not been affected by colony collapse disorder.

Mussen said that unlike honeybees, mason bees need a cold snap followed by a specific number of heat units to prepare them for hatching. "That normally coincides almost perfectly with apples."

However, these temperature requirements can be manipulated so that the hatch will coincide with blooms of other crops, such as almonds.

Seattle-area mason beekeeper Steve Brustkern said he keeps some of his developing bees in the refrigerator to prolong the cold period and thus have the bees available for late-maturing crops, like sweet cherries. Mussen said that because of colony collapse disorder that's affecting honeybee populations around the country, the California Almond Board is studying mason bees as a source of relief.

One study is taking place in Bakersfield, where Brustkern has 20,000 of his masons. The study is looking at, among other things, how quickly mason bees can be ramped up when starting with reasonable numbers.

Mason bees don't come cheap, up to 80 cents apiece, Brustkern said.

Mussen said that regardless of the cost or the number of masons needed, "if honeybees disappear, almond growers would come up with the money to pay for almost anything to help them."

Mason beekeepers would have a Herculean task if that should happen, given that about 600 million honeybees are needed to pollinate the huge California almond crop.

Mussen said that despite CCD, California almond pollinations in 2006 were not affected from a production standpoint. "We got the heaviest nut crop we've ever gotten. And probably got the largest number of nuts ever, but they were small."

Salem beekeeper Harry Vanderpool, who runs about 300 honeybee hives, views mason orchard bees as "very, very important wild pollinators" that work best in small settings, such as home gardens and hobbyist orchards.

Furthermore, based on the studies going on in Bakersfield, Vanderpool does not rule out masons playing a more active role in almond pollinations. "We'll see," he said.

But for the time being, when it comes to monocultures consisting of hundreds of acres, masons aren't up to the task, Vanderpool said. "You bring in bees, and all it takes sometimes (during ideal conditions) is three hours for honeybees to completely set (that crop)."

One drawback some ascribe to mason bees is that once they leave the brood tube, they seek out another place to nest.

Brustkern countered, saying that mason bees normally only travel 100 to 200 yards from the release site, and will "likely return" to the hatch area, where they live in man-made nests. - John Schmitz

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