Plan Bee: As Honeybees Die Out, Will Other Species Take Their Place?

In a race against time, researchers propagate native solitary bees as an alternative to our most important pollinators
Christopher Mims, Scientific American 31 Mar 09;

Honeybees have been dying in record numbers in the U.S. for at least the past two years. Experts attribute the mass deaths to a catchall condition known as colony collapse disorder (CCD), although both a cure and the culprit remain elusive. Despite as much as a 35 percent loss of bees per year, we remain almost entirely dependent on what until recently was a self-renewing annual population of billions of honeybees to pollinate over 130 kinds of fruit and nut crops.

"We can't rely on the honeybee forever," says Blair Sampson, an entomologist with the U.S. Department of Agriculture (USDA). That's a problem, given that entomologists have yet to come up with a viable alternative.

But researchers report that another bee known as the blue orchard, or Osmia lignaria, holds out promise of filling in the void.

The blue orchard bee, also known as the orchard mason bee, is one of 3,000 bee species native to the U.S. and is currently the subject of intensive study by the USDA's Pollinating Insect Biology, Management and Systematics Research Unit at Utah State University in Logan.

James Cane, an entomologist at the Logan bee lab, has been working for 10 years to increase the availability of these bees and he says there are now a million blue orchards pollinating crops in California.

The reason these bees are considered the best potential honeybee stand-ins, Cane says, is that unlike some specialist native species, blue orchard bees, like honeybees, can pollinate a variety of crops—including almonds, peaches, plums, cherries, apples and others.

In just about every other respect, however, these bees are totally unlike their European brethren. For one, they tend to live alone. In the wild, rather than hives, they inhabit boreholes drilled by beetles into the trunks and branches of dead trees. When cultivated, they will happily occupy holes drilled into lumber or even Styrofoam blocks.

The blue orchard bees also do not produce honey, rarely sting and, owing to their solitary nature, do not swarm. They are incredibly efficient pollinators of many tree fruit crops—on a typical acre, 2,000 blue orchard bees can do the work of more than 100,000 honeybees. Their biggest drawback is that beekeepers can only increase their populations by a factor of three to eight each year. (Honey bees can grow from a small colony consisting of a queen and a few dozen workers to a population of 20,000 foragers in a few months.)

"We're still in the development stage of applying all the research that has been done" by USDA's Agricultural Research Service, says David Moreland, CEO of AgPollen, the world’s leading producer of blue orchard bees for the California almond industry.

Of the nearly 700,000 acres (285,000 hectares) of almonds cultivated in California this growing season, as many as 300 acres (120 hectares) were pollinated by blue orchards, according to Moreland. Growers' inspiration for trying the new pollinator is simple economics—last season they were paying up to $300 to rent a single hive of honeybees, 10 times what they paid a decade ago. This trend has made blue orchard bees cost-competitive with honeybees, but only barely.

"It's not clear we can [raise blue orchard bees on a commercial scale] in a cost-effective way," says Karen Strickler, an entomologist at the University of Idaho from 1993-2000 who has worked with solitary bees and who currently distributes them to beekeepers and hobbyists through the bee dealership PollinatorParadise.com, located in New Mexico.

Another solitary bee, known as the leaf-cutter, is the success story on which scientists and beekeepers hope to model the trajectory of the blue orchard bee.

"Ninety percent of all alfalfa seed in the U.S. is grown using the alfalfa leaf-cutter bee for pollination," Moreland says. "That's huge—that's an industry that over the past 25 years went from zero to the preferred bee. So there's a model there that says: 'This has happened before, it can happen again.'"

Cane, described by his peers as one of the world experts on orchard bees, cautions that these bees currently can only supplement—and not supplant—honeybees.

"The sheer number of bees you would need—at least 500 per acre (0.4 hectare)—it will never replace honeybees," says Cane. "That's an outrageous number if you think about it."

AgPollen's Moreland is more optimistic. "If we got to the point that we could not maintain populations [of honeybees]," he says, "this is one way to ensure that the largest dollar specialty crop in California for export—the almond—doesn't lose its pollinator."

Is Life Too Hard for Honeybees?
Researchers zero in on the culprits behind colony collapse disorder
Wendy Lyons Sunshine, Scientific American 31 Mar 09;

Commercial honeybees are tough. They get trucked cross-country to pollinate vast crops, often while fed unnatural diets such as sugar water and soy flour. Their hives are treated with chemicals to deter parasites, and they're exposed to pesticides and fungicides in the fields where they work and feed.

"I can feed you a diet of Hershey bars, keep you up all night, truck you around, and spray Raid in your face, and I guarantee you'll get sick," says Jerry Hayes, Florida's assistant chief of apiary inspection. "That's kind of what's happening to bees."

Just how much physical abuse do honey bees face? And what are the implications? Those questions inform research into colony collapse disorder (CCD), a phenomenon that has killed over a third of commercial honeybees in the U.S. and some European countries since 2006. With no obvious cause, scientists have begun examining how beekeeping practices and environmental contamination may be impairing hive immunity.

CCD research poses challenges, because stricken bees disappear, taking forensic evidence with them. Lab experiments offer clues, but translating those into reliable, controlled field studies poses difficulties, because bees roam for miles. Still, with valuable crops such as almond, apple, blueberry and others at stake, even ordinary citizens are trying to help.

"The interest from the general public has been tremendous," says entomologist Jeff Pettis, lead researcher at the U.S. Department of Agriculture Agricultural Research Service's (USDA–ARS) Bee Research Laboratory in Beltsville, Md. He has received phone tips and even jars of bees from people hoping to help solve the mystery. Lately, he tells them several suspects have already been ruled out, including tracheal mites, small hive beetles, genotype differences, cell phone exposure, melamine contamination and genetically modified crops.

"For almost two years we've been documenting and sampling colonies that are dying and examining healthy colonies in the same area, trying to determine what factors are involved," Pettis says. "I think there are interactions going on, like low-level pesticide exposure and poor nutrition weakening the host honeybees and then pathogens doing the killing. It's similar to a human who might not be eating, or is frail and traveling too much, and as a result is more susceptible to pathogens. If you go into a hospital in excellent health, you don't contract pneumonia, but if you go in weakened, pneumonia kills you."

Pesticides and fungicides
How much pesticide exposure is too much for a honey bee? Traditionally, Pettis says, manufacturers seek clearance for pesticides by using the LD-50 test, which "essentially applies toxic stuff to bees and sees if half or more of them drop dead." This brute force test does not, however, gauge long-term systemic effects.

"The general feeling is that we need to move beyond mortality testing to sublethal testing that looks at the shortening of life span, disorientation, reduced vigor, and other things," says Pettis, who has been in discussions with the U.S. Environmental Protection Agency (EPA) about developing newer, more sensitive pesticide tests.

EPA spokesperson Dale Kemery says that the EPA's Office of Pesticide Programs, industry stakeholders, and academics have huddled at least twice over the past six months to discuss additional pesticide testing. He refused to provide details of the meetings.

Pesticide residues show up in a variety of ways. For example, "entombed pollen" in the hive can display pesticide and fungicide content, according to a study by Pennsylvania State University researchers and Pettis now in press at the Journal of Invertebrate Pathology. Pettis says he is working on additional pesticide studies that may provide important new insights into hive risks.