How farmers are using native mason bees to boost crop production

BOTHELL, Wash. — Jim Watts calls himself a farmer, but he doesn’t raise livestock or crops. Watts is a bee farmer.

Across the West, growers are turning to a tiny, overlooked insect to pollinate crops: the native mason bee. In Washington state, Watts is leading the movement.

Researchers call mason bees “the new frontier” for crop pollination.

In recent years, many farmers say they have bought or rented mason bees because they are affordable, low maintenance, improve crop yields, repopulate areas with native species and even push honey bees working alongside them to be more efficient.

Researchers have known about mason bees’ pollinating potential for decades, but their use in agriculture has been overshadowed by the ubiquitous honey bee.

USDA’s most recent data show farmers in the Western U.S. spend more than $300 million annually on crop pollination by honey bees. Western farms use honey bees in dozens of crops across millions of acres. For example, 2020 reports show California farms are using honey bees to pollinate 1.2 million almond acres, and Northwest farms this year are pollinating nearly 300,000 fruit tree acres.

Until recently, large-scale propagation of mason bees has been a pipe dream.

Now, it’s taking wing.

Story of a bee farmer
Watts, owner of Watts Solitary Bees, grew up on a bee farm. His dad, Roger, started raising leafcutter bees, best known for pollinating alfalfa, in the 1960s. When Jim Watts grew up, he and his family took over the business, which his dad still helps with today.

Around 2008, Watts decided to try propagating mason bees. For eight years, he floundered, failing to replicate nature. Those eight years, he didn’t make a dollar and often ran in the red.

“I wanted to quit,” said Watts. “But my dad kept saying, ‘Keep doing it. It’s going to work.’ We finally got it right. Now we’re producing millions of bees and we plan to keep expanding.”

Watts Solitary Bees has two divisions: a commercial side that sells mason and leafcutter bees to large-scale producers, and a rental side, called Rent Mason Bees, that rents bees to small farms, backyard gardeners and urbanites.

The rental program, city dwellers say, teaches people where their food comes from and helps build bridges in a time when tensions are high between rural and urban communities.

Different kind of bee
Most people are only familiar with honey bees, but there are more than 20,000 bee species worldwide and more than 450 in Washington state alone, said Katie Buckley, pollinator health coordinator at Washington State Department of Agriculture.

Early European settlers introduced honey bees to North America; mason bees were natives. People have domesticated honey bees for thousands of years, Buckley said, but mason beekeeping is relatively new.

Entomologists say mason bees are different from social honey bees. The mason bee prefers to be left alone. It is gentle, doesn’t have a fancy hive and dresses a bit like the common fly. It has no queen to protect, because every female is fertile. Because of its solitary nature, it is less likely to pass along illness. It braves the rain and works in colder weather. It nests in a cavity and lies dormant all winter, tucked inside a tiny, hard cocoon. It doesn’t produce honey. And in many crops, mason bees outperform other pollinators.

Belly floppers
“Mason bees are clumsy and they belly-flop onto flowers. It’s so funny to watch,” said Thyra McKenzie, a Seattle resident who rents mason bees each year for her backyard.

Entomologists say mason bees are effective pollinators partly because of how they carry pollen. Honey bees wet pollen to make it sticky and carry it in baskets on their legs, but mason bees belly-flop onto flowers, then carry dry pollen on their abdomens. As they travel flower to flower, flecks fall off, doing the work of pollination.

Mason bees are also generalists, said Olivia Shangrow, biologist for Rent Mason Bees. Shangrow said honey bees are specialists that work systemically, but mason bees pop here and there, appearing “distracted,” which makes them great cross-pollinators.

Bee alternative
“Everybody’s nervous about colony collapse disorder in honey bees,” said Brian Bly, a grower with 9,000 almond acres at Hart Farms in Orland, Calif. “My farm is so reliant on pollinators, so we got mason bees as a plan B, a sort of insurance policy.”

Bly bought his first batch of 100,000 mason bees five years ago — not to replace honey bees, but to complement them.

Studies from Stanford University and USDA have shown a hive of honey bees is healthier, less stressed and twice as efficient when working alongside other pollinators.

Before using mason bees, Bly rented honey bees at $200 per hive, two hives per acre. Each hive contained up to 30,000 honey bees.

But because mason bees are more efficient pollinators, fewer are needed per acre. Bly said when he puts 1,000 mason bees on an acre, he only needs to rent one honey bee hive instead of two, cutting costs.

Bly said he also likes working with mason bees because they are easy to care for.

Watts estimates mason bee care takes about 20 minutes of setup-teardown per acre each year, plus a few days per 100 acres each fall opening nesting blocks, cleaning cocoons and putting hibernating bees in cold storage for the winter.

Some farms, Watts said, are also excited about marketing their food as “pollinator friendly” or “pollinated with native bees” to meet growing consumer demands.

“I’m very excited about the mason bees and I hope to keep expanding,” said Bly.

Bly said he hasn’t measured the difference in production yet, but when his honey bees are still inside their hives on cold mornings, he sees the mason bees outside working.

Some farmers have measured. One California almond grower who purchased mason bees from Watts Solitary Bees said his trees yielded 800 pounds more nuts per acre.

Through entomologists’ eyes
Compared to honey bee research, mason bee studies are relatively uncharted territory, so it’s hard to quantify how efficient mason bees are, said Theresa Pitts-Singer, entomologist at USDA’s bee lab.

Researchers do know mason bees are especially good at pollinating fruit trees such as apples and plums, said Buckley, WSDA’s pollinator health coordinator. Studies have also confirmed their effectiveness in pollinating almonds, early raspberry varieties, cherries and pears.

Lisa Horth, professor of biology at Old Dominion University in Virginia, found in a series of studies that using mason bees to pollinate strawberries makes berries “substantially larger.”

Horth said she’s involved in studies happening now tracking mason bee use in other crops. Although Horth said she can’t reveal details yet, she said the results are “amazing.”

What farmers should know
Researchers say they think the “mason bee revolution” is coming, but there’s a lot farmers should know first.

Just like honey bees, mason bees have adversaries. Buckley of WSDA said special nesting blocks should be used to keep out enemies, including Houdini flies and predatory wasps. Farmers should also do an annual cocoon cleaning to remove pollen mites.

Some bees will naturally disperse into the wild, making their nests in hollow stems, rockeries or woodpecker holes, said Shangrow, biologist for Rent Mason Bees.

Experts say putting a football-sized chunk of wet clay or mud every acre makes mason bees more likely to stay because they mud-cap their holes. To encourage bees to stick around, Buckley also encourages farmers to plant native shrubs and flowers around fields.

Mason bees only fly in a 300- to 400-foot radius from their nest, so farmers need to disperse nesting materials throughout their acreage. Watts Solitary Bees offers on-site consultations.

Farmers also need to plan ahead for their anticipated bloom date. Mason bees typically pollinate March through May, Watts said, but can be managed to fly earlier or later.

Adult mason bees hibernate in cocoons over winter. Bly, the California almond grower, simulates winter by keeping his bees in a climate-insulated container starting in August so they wake up to February almond blossoms.

But nature can only be bent so far, and entomologists say waking bees up too early or too late can kill them. Researchers say farmers should consult with bee experts.

Horth of Old Dominion said she has great respect for farmers of all kinds, organic and conventional, but said bees are safer on no-spray farms.

The well-known reason is that pesticides can kill adult bees if sprayed incorrectly.

The lesser-known reason is based on a discovery University of Wisconsin-Madison researchers made in 2019. In their larval state, mason bees are omnivores, feeding on tiny microbes in pollen. Farmers who spray insecticides may inadvertently kill larvae, which need microbes in their diet.

A farmer’s success with mason bees, Watts said, depends on their attitude and how closely they follow instructions.

Bee farming
Jim Watts is not the only mason bee producer. Entomologists say a few smaller-scale mason bee farmers are scattered throughout the U.S.

One is Dave Hunter, owner of Crown Bees in Woodinville, Wash.

Hunter recalls mason bees first caught his attention 20 years ago when his wife noticed the neighbors’ apple tree was drooping with ripe apples while their own tree was almost bare. When Hunter realized the neighbors had mason bees, he drilled holes in a block of wood to lure the bees with a nest and — voila! — the apples did better the next year.

Hunter started Crown Bees 12 years ago. Unlike Watts, he’s not yet at the commercial farm scale. Instead, he sells wholesale to about 500 nurseries and hardware stores across the nation, including Wilco. He said he is continuing to grow the business and hopes to reach commercial-scale farmers “soon.”

Bridging urban-rural divide
Perhaps the most inventive part of Watts Solitary Bees is its Rent Mason Bees program, designed to work in conjunction with its commercial side.

Over the past few years, thousands of people in suburban and urban areas have rented mason bees through the company, said Shangrow, the program’s biologist. The company sells rental kits of 60, 120 or 240 bees.

Shangrow said the program teaches people where their food comes from, pollinates backyard gardens and repopulates areas with native bees because some of the bees fly away.

By following simple instructions, renters encourage bees to breed, then ship young cocooned bees back to the company. Some of these bees will be put back in the program and end up in other renters’ backyards next spring; others will end up on farms, meaning city dwellers help raise bees for farms.

“I think native bees can be part of bridging the urban-rural divide,” said Watts.

McKenzie, the Seattle resident, started renting mason bees four years ago.

“My husband had been dead-set on getting honey bees. But come on. My little boy and his friends in a tiny backyard? That’s just asking for trouble,” she said.

When McKenzie learned about nonaggressive mason bees, she bought a rental kit.

“Now I’m hooked,” said McKenzie.

With her kids home from school this spring during the COVID-19 shutdown, McKenzie said the bees were an educational project about science, food and farming.

During the shutdown, hundreds of families stuck at home turned to Rent Mason Bees as a backyard science project.

Mason bee season is wrapping up for 2020, and Watts said orders for next year open this fall.

Beekeeping taking flight
Mason beekeeping is growing, but it still has a long way to go, researchers say.

Contrasted with millions of crop acres across the U.S. pollinated by honey bees, farms only raise mason bees on about 1,500 acres, said Watts.

But barriers are crumbling.

In 2016, mason bees cost upwards of $1 per bee. Now, Watts said he charges about 30 to 40 cents per bee. In the next few decades, experts predict the price per bee will fall to 5 cents.

“French wine is to the honey bee exactly what California wine is to the mason bee,” said Hunter of Crown Bees. “The honey bee industry is enormous and gets a lot of attention, but mason bees are the up-and-coming pollinators.”

More research about mason bees is underway, but it will take time and researchers will need farms to participate in experiments.

“I strongly believe this industry is at its tipping point,” said entomologist Pitts-Singer. “I’m very hopeful that after 40 years of knowing this bee was a good pollinator, its popularity will finally take flight.”