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March 11, 2010

Plight of the honeybee

A team of Utah scientists are finding ways to replace our dwindling honeybee population.

Straight out of the refrigerator, BOB doesn’t look like much.
In fact, with its tiny crumpled legs, tight wings and listless antennae, the creature in my hand looks dead, not just hibernating. Even after I hold it awhile and it warms up, crawling sluggishly across my palm so I can see its metallic blue body and transparent wings, the blue orchard bee—Osmia lignaria, or BOB, as the insect is known to the entomologists here at the bee lab at Utah State University, where my sleepy bug lives—is not that impressive. But to those in the know (tree fruit farmers, almond growers and entomologists), BOB is turning into a bona fide bug hero.
 
Here’s why: In the 21st century—in spite of all our technological and biological wizardry—“one out of every three bites we put in our mouths depends on insect pollination,” points out apiarist Darren Cox. And, as you’ve no doubt heard, our honeybees are disappearing alarmingly, and mysteriously.

The bee lab at USU was founded in the 1940s to study the honeybee—
Apis mellifera, to call it by its scientific name. It has since evolved into a “non-apis” bee lab, says Dr. Rosalind James, research leader at the Agricultural Research Service’s Pollinating Insect Biology, Management, and Systematics Laboratory at USU.

“Honeybees are the world’s main pollinator. But they are in crisis. Our mission is to find other species to aid in pollination.”

THE PROBLEM, IN A NUTSHELL
California is the only state in the country that produces almonds commercially, and it produces 80 percent of the world’s supply. There are 6,000 almond growers in California cultivating 600,000 acres. In 2004, their crop produced nearly $1 billion in almonds.

More than 1.2 million bee hives are required to pollinate California’s almond orchards—almond trees need at least two hives per acre. That means more than half the honeybees in the United States are moved to California to pollinate the almond crop for the season. For Cox, a fourth-generation Utah beekeeper, that means leaving his home in Logan on December 26 and basing his life in California until sometime in April.

Here’s the kicker: In the last 30 years, more than half the honeybee colonies in the country have perished. There are lots of villains killing honeybees, but the latest is a mysterious ailment called “colony collapse disorder.” No one knows exactly what causes CCD, or where it came from, but most beekeepers and experts agree the health of the entire United States honeybee population is seriously at risk.

And therefore, in the domino-tumbling game of modern mono-agriculture, our supply of almonds, blueberries, cranberries, cherries, cucumbers, watermelons, cantaloupes and pumpkins, and seed crops like alfalfa, is threatened.

Even before the onset of CCD, honeybees were in trouble: varroa mites, chalkbrood fungus, habitat loss and pesticide use have all taken their toll. “We’ve maxed out the capacities of the honeybee,” says Dr. James Cane, an entomologist at the USDA American Research Services bee lab in Logan.

Cox estimates that he lost 1,000 hives last year to misuse of pesticides, mostly by homeowners, not farmers. In April, the Seattle Times reported that yet another new bee pathogen had been detected, further threatening Washington state, where eight out of the state’s 10 most valuable crops, including apples, depend on honeybees for pollination.
 
Add to the honeybee’s health problems the challenge that a modern farm’s vast acreage presents to a tiny, six-legged pollinator and the documented decline of the bumblebee (the primary pollinator of hothouse tomatoes) and you reach a bee crisis. Which is where our friend BOB—and the whole bee team housed at USU—enters the picture.

A BEE FOR EVERY BLOOM
There are nearly a million specimens and 6,850 species of bees in the National Pollinating Insects Collection housed at USU, one of the best in the world, says Dr. Terry Griswold, the research entomologist who curates the collection.

Thousands of bees don’t take up that much space; the bee library at USU is a modest-sized room on the second floor of the biology building. Sliding drawers reveal arrays of bees pinned on cards. They range from barely visible specks to furry giants. Much of the collection has been digitized, so it is available for public use.

Citizen scientists and amateur beekeepers are important to the world of bee science, just as backyard birders are to the study of birds. “New species of bees are still being discovered,” says Griswold, “especially in southern Europe and Turkey, but even in the United States.”

Honeybees are not native to North America. They arrived with the European settlers, as early as 1621, made their way across the continent with the pioneers, and generally thrived until another immigrant, the bloodsucking varroa mite, was accidentally imported and nearly wiped out the feral honeybee population during the 1980s and ’90s.

Even without wild bees and with the reduced numbers of managed bees, honeybees are the main pollinators used in agriculture. But they are not the only pollinators—butterflies, bats, birds and wasps and about 20,000 other species, worldwide, all help with pollination.

“In China, where labor is cheap, orchards are still hand-pollinated,” says Dr. James Strange, the bumblebee specialist on James’ team.
 
He makes the remark as he walks between the young tomato plants in the lab greenhouse, mimicking a bee’s pollen-loosening buzz by flicking the flowers with his fingers. “You can’t use honeybees in a greenhouse,” says Strange. “That’s why bumblebees are used for hothouse tomatoes.”

Honeybees are not always the best pollinators. Like bumblebees, honeybees are generalists and will visit all kinds of plants. Their strength is the diversity of their appetites—they will travel a long way, pollinating all kinds of flowers blooming at different times. That’s not necessarily an advantage when you’re trying to grow thousands of acres of a single plant.

Our friend, BOB, and the other bees under the microscope at USU’s bee lab, are specialists—they have definite preferences of plants to visit. BOB loves fruit blossoms. And the native squash bee “just won’t nest without squash,” says Cane.

BOB is also native to the western United States. Introducing non-native species as ecological problem solvers has sometimes resulted in disaster, as anyone who has driven through the kudzu-clogged forests in Georgia and Alabama knows. The fast-growing Japanese plant was introduced as a means of managing erosion; now it grows out of control and costs $500 million a year in lost cropland and control efforts. Scientists now are much more cautious. “At least, now we know we don’t know what will happen when we introduce a new species,” says Griswold.

Most important, the Utah scientists claim, BOB is a more efficient pollinator of almonds and other tree fruits than the honeybee.
 
Entomologists William P. Kemp and Jordi Bosch, both formerly at the Logan laboratory, conducted a four-year experiment at a commercial cherry orchard in northern Utah, ending  in 1998. They measured cherry harvests before and after introducing blue orchard bees and found that production was more than twice as high when blue orchard bees were used instead of honeybees.

Just 250 to 300 female blue orchard bees can pollinate a whole acre of fruit trees—rather than 60,000 or more honeybees—and they are less choosy about the weather, continuing to forage and pollinate even when skies are gray and temperatures cool. So, even in bad years, orchards pollinated by blue orchard bees produced marketable fruit.  

THE BEE'S NEEDS
The blue orchard bee isn’t the only backup bee being studied at the bee lab. Pollinators are vital to production of commercial seeds—broccoli, carrots, lettuce, clover and Utah’s largest cash crop, alfalfa.
 Alfalfa leafcutter bees are not native—they were accidentally introduced in the U.S. some time in the ’40s and by the ’50s had established themselves as wild. Their appetite for alfalfa pollen made them one of the first bees studied at the USU lab.

 “They are better pollinators of alfalfa than honeybees, and using alfalfa leafcutter bees upped seed production significantly,” says James. Yields of alfalfa seed rose from 100 pounds per acre in honeybee-pollinated fields to 600 or 1,000 pounds per acre in fields pollinated by leafcutters.

Interaction between field and bee is one thing; human-bee interaction is more complicated. Honeybees are easy to manage because they naturally live in colonies of hundreds and thousands in a single hive. But—despite their reputation as the most social of animals—most bees are loners, and solitary bees are harder to manage.  

“The leafcutter is a solitary bee. Each one is a queen. They nest near each other, but each has its own nest,” explains James. “We need to figure out how to build populations that can be managed, like honeybees.”

How many alfalfa leafcutter bees per acre result in the maximum crop yield and the best bee health? What are the best flowering plants to raise BOB? These are the kinds of questions the team at USU is trying to answer.
 How do you adapt the life cycle of a bee to the life cycle of an almond tree? Or a tomato plant? It turns out you have to force bees like you do flowers—chill them for awhile, then warm them up and feed them. You have to provide them with suitable nesting holes—but how many solitary bees will live happily in proximity?
 
Dr. Theresa Pitts Singer is investigating the chemically mediated behavior of these solitary bees. “We know, for example, that these bees prefer used nests. We want them to prefer our nests. So we need to find out how they mark their nests. Do they mark them with wax? Do they imprint on the nest as larvae? We need to understand the ecology of these insects in order to manage them.”

MAN VS. NATURE
These questions become more urgent as the honeybee problems become more pressing. The enormous demand for honeybee pollination, just in California’s almond orchards, has inflated the cost of bee rental from $50 per hive in 2003 to $140 per hive today. That, in turn, has spurred episodes of bee-napping.

In March, an Associated Press headline read, “Rustlers are going after livestock in the West.” But the “livestock” in this story has six legs: Bee snatchers are stealing hives. Then they rent the stolen bees to farmers and pocket the pollination fees. Hundreds of hives were stolen this season—another threat to the honeybee’s hegemony.

“Adapting to a new bee costs money,” points out Strange. It is expensive to change from one pollination system to another. But an estimated $14 billion in agricultural crops in the United States depends on bee pollination. And that’s just the dollar count.

More than 100 million years ago, bees and flowers became co-dependents—flowers are designed to attract bees to survive and bees depend on flowers to survive. The system is beautiful. For example, our native squash bees evolved in tandem with a native plant. “One unmanaged pollinator is responsible for an entire crop’s proliferation across the hemisphere,” says Jim Cane.

But as the scale of agriculture increases, we’re losing wild pollinators. “There’s a monoculture of pollinators now, like there is of agriculture. We need a diversity of pollinators,” says Griswold. “You begin to realize how complex the services are that nature provides.”

“We’re pushing our ecological system to the maximum capacity. Leaving things to nature now means leaving it to humans. The question is, can we keep it in balance?”    

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