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Wednesday, April 25, 2007 01:41 am

BEEwitched, Bothered, and BEEwildered

Illinois scientists search for the reasons bees are dropping like flies

Untitled Document The first reported disappearances came late last year in Florida. By January, investigators had determined that millions of individuals had gone missing, leaving few if any clues as to why. The bizarre phenomenon has prompted a nationwide scientific inquiry. In late March, a congressional subcommittee held a hearing on the matter. As the quiet debate over the issue continues in the halls of government and university laboratories, the body count has risen with each passing day. Authorities in more than two dozen states have now verified similar cases. Disappearances have also occurred recently across Canada and Europe. If it were happening to a larger species, the plight of Apis mellifera would likely have spurred greater public outcry. Instead, the mass annihilation has stayed mostly under the radar. But the dire situation has raised concerns among some scientists who are struggling to understand it.  “We don’t actually know what the cause of the problem is in honeybees,” says May R. Berenbaum, an entomologist at the University of Illinois at Urbana-Champaign, “but one possibility is pesticide overload.” The scientist cautions that there are many other possible causes. She and fellow entomologist Gene E. Robinson, who is responsible for mapping the honeybee genome, are among the top researchers delving into the mysterious malady, which has been dubbed “colony-collapse disorder.”
Commercial beekeepers across the United States are reporting colony losses from CCD of as much as 80 percent so far this year. Worker bees are simply not returning to their hives. The absence of corpses in or near the hives has led researchers to surmise that the insects have lost their innate ability to make a beeline home. Something is causing the bees to become disoriented after collecting nectar from flowering plants. Their natural navigation systems have been thrown out of whack. They are presumed to buzz around until they drop dead from exhaustion.
The alarming decline in these tiny foragers affects more than just honey production. Honeybees are also used to pollinate more than 90 fruit and vegetable crops in North America. Commercial beekeepers move their hives from state to state, selling their pollination services to farmers. Severe reductions in honeybee colonies would have a devastating impact on America’s multibillion-dollar agricultural economy and, ultimately, a sizable portion of its food supply. Although grain crops, which are pollinated mainly by the wind, would not be widely affected, apples, almonds, and broccoli are entirely reliant on honeybees. Approximately one-third of the U.S. diet depends on honeybee pollination. A national study published seven years ago put the estimated annual value of bee-pollinated crops at nearly $14.6 billion.
The honeybees’ dilemma did not, however, begin with their recent disorientation. Populations have been waning for decades — dropping, according to one estimate, by more than 40 percent since the middle of the last century. In the mid-1980s, the introduction of two types of bloodsucking parasitic mites exacerbated the decline. The parasites are believed to have decimated populations of feral honeybees, too. In a statement submitted to the House Subcommittee on Horticulture and Organic Agriculture on March 29, Berenbaum warned that “if honeybee numbers continue to decline at the rates documented from 1989 to 1996, managed honeybees will cease to exist by 2035.”
Faced with the elimination of a huge percentage of their colonies, many commercial beekeepers went out of business in the 1980s, leaving the remainder of the industry hard pressed to meet the growing demand for services. Two years ago, colony shortages in California led to the first importation of foreign bees since the passage of the Honeybee Act of 1922. With so much riding on these creatures, Berenbaum is astounded by the overall lack of apicultural knowledge. “Considering how incredibly important economically honeybees are, we really know pathetically little about them,” she says. “We don’t even count them properly.”
She discovered the loose accounting procedures last year while chairing a National Academies of Science research committee charged with monitoring the status of North American pollinators. Berenbaum reiterated her findings to Congress last month. “There is an extraordinary paucity of reliable data on pollinator populations,” she testified. “This dearth surprisingly applies even to the honeybee, a species that has been semidomesticated and managed for thousands of years.” Among other regulatory deficiencies, Berenbaum pointed to longstanding Agriculture Department surveys that gauge only honey production, not pollination services. Berenbaum, who refers to honeybees as “six-legged livestock,” attributes the lax governmental oversight in part to “a cultural bias against small things.” In her congressional testimony she stated: “It is difficult to think of any other multibillion-dollar agricultural enterprise that is so casually monitored.”
Honeybees have been taken for granted, says Berenbaum, even though they have been essential to American agriculture since 16th-century colonialists imported them from Europe to pollinate their apple orchards. Though the scale of operations has vastly increased, beekeeping methods remain much the same as they were in 1852, when Lorenzo Lorraine Langstroth, a Philadelphia clergyman, patented the movable-frame hive. With the exception of pesticides used to fight parasites, the artificial insemination of queen bees, a technique developed in the early 20th century, is considered by many the most recent innovation in beekeeping. But CCD has created an urgent impetus for change. The direction of that change is yet unclear, but there is a high probability that genetic research will play a role as scientists move forward in seeking to stem honeybee losses. In October 2006, only a month or so before the disorder came to light, the Honeybee Genome Sequencing Consortium published its finding in Nature magazine. Robinson, co-leader of the project, helped generate a honeybee gene chip containing 11,000 genes. Together with Berenbaum, he is poised to cooperate with other scientists at Penn State University and elsewhere to help uncover the secrets of CCD. “One possibility we’re exploring is that the bees have encountered some kind of toxin or another in the environment due to pathogens or parasites or pesticides,” says Robinson. “We’re going to be looking particularly to see if we see any hint of that sort of response in the CCD bees.”
The research will involve comparing the gene activity of CCD-affected honeybees with their healthy counterparts. “The genome sequence gives us a parts list,” says Robinson. Researchers will be looking for genetic differences between the two groups. “If there is gene activity, the next question is, in what genes do we see the changes?” he says. “After we ask that question, the next issue is, do the identities of those genes give us any insight.” If genetic alterations are discovered, Robinson says, researchers will analyze their findings to determine whether genes known to respond to pathogens, parasites, pesticides, or other causal factors have triggered changes in CCD-affected honeybees.
The sequencing of the honeybee genome has already revealed at least one disturbing characteristic. “Honeybees have a vastly reduced inventory of detoxification genes,” Berenbaum says. “They have the smallest known inventory in this gene family of any insect. Fruit flies have 90 detoxification enzymes. Honeybees have about half that.” Scientists don’t know why, but they hypothesize that honeybees, which thrive in colonies of 30,000 or more, naturally shield themselves from outside dangers through their social environment. “But we may have ratcheted up the amount of unpleasantness to a level their system can’t handle,” Berenbaum says. The “unpleasantness” may be rooted in a number of natural or manmade causes or a combination of factors, including viral, bacterial, and fungal diseases. Other possibilities include dietary supplements, climate, and stress related to transport over long distances. The latest theory, posited by researchers in Germany, is that cell-phone signals are causing the disorientation. “I’ve been inundated with people who say that it’s got to be GM [genetically modified] corn pollen,” Berenbaum says. “If it’s GM corn pollen, why isn’t there a single case of colony collapse in central Illinois, where we’re in an ocean of GM corn pollen?” she asks. “Cell phones, wireless Internet, Osama bin Laden, alien abduction, chemical contrails [from] jet planes — people have sent me e-mails suggesting all of these things.”
Besides pathogens, pesticides remain one of the more plausible explanations for CCD. In 1999, the French government banned the use of Gaucho brand pesticide on sunflower seed because beekeepers in France strongly suspected the chemical of causing the same inexplicable behavior now associated with CCD. The European press called it “mad-bee disease.” A few years later, the French extended the ban to corn seed for the same reason. German-based Bayer CropScience, the manufacturer, denies responsibility for the bee die-off in France. Bayer referred all questions on the French ban and other issues to CropLife America, the national association that represents the pesticide industry. Spokeswoman Donna Uchida confirmed that the French ban on Gaucho remains in effect even though the French government acknowledges that the mortality rate among honeybees has continued to increase since farmers quit using the pesticide. “The cause of colony-collapse disorder is really unknown at this point,” says Uchida. “The pesticide industry really supports the importance of researching bee-health problems, because if farmers don’t have crops because there is no pollination, then nobody would have a need for our products, either.”
Imidacloprid — the chemical ingredient in Gaucho — is used to treat corn seed and for an array of other agricultural and pest-control purposes in the United States and 70 other countries. It was first registered for use in the United States in 1992 and is marketed by Bayer under various brand names to kill fleas on pets, larvae in lawns, and many types of beetles, aphids, and other insects in farm fields. When applied as a seed dressing, imidacloprid moves up the plant stem and into the nectar and pollen, where honeybees and other pollinators come into contact with it. It is also sprayed directly on a wide range of crops, including grapes, potatoes, soybeans, and sugarcane.  Imidacloprid is one of a group of insecticides known as neonicotinoids, which are forms of synthetic nicotine that attack the nervous systems of insects. A Congressional Research Service report published last month noted that some beekeepers in the United States, United Kingdom, and France have voiced concerns about imidacloprid. The beekeepers fear that the chemical may “affect complex behaviors in insects, including flight navigation, olfactory memory, recruitment, foraging and coordination.” Moreover, in 2003, the Environmental Protection Agency warned that a related chemical — clothianidin — has the “potential for toxic chronic exposure to honeybees, as well as other non-target pollinators.” The EPA report recommended further study. “There are efforts now [at Penn State and elsewhere] to determine what the precise field effects are to these neonicotinoids,” Berenbaum says. The scrutiny is warranted “because in laboratory studies they have been shown to have sublethal effects on behavior,” she adds. “The fact that corpses are not accumulating in front of the colony suggests that they [honeybees] are not returning home and that perhaps their navigational systems are being compromised, which neurotoxins can do. [But] it’s not a slam-dunk. It’s a suggestion.”
In the absence of conclusive field results, Berenbaum is reserving judgment. “Imidacloprid sales have been flat for the last few years,” she says. “There’s no compelling evidence for or against it, frankly. It’s not like there’s only one pesticide out there. Some people think it’s a combination of multiple exposures to different kinds of pesticides.” On the other hand, Berenbaum says, “There are a number of people who believe that it is a new pathogen, which is totally plausible as well. There are many viruses that affect insect behavior.”
Part of the problem that agriculture now faces has been caused by overreliance on a single species to pollinate crops. In that regard, Berenbaum advocates taking such steps as creating a federal program to set aside land as habitat for wild pollinators — but she also seriously doubts that wild pollinators can ever be coaxed into carrying the load now shouldered by honeybees. To secure their future and a hefty part of the American agricultural sector, she asserts that lawmakers must allocate more funds for research purposes when Congress reauthorizes the Farm Bill later this year. In the meantime, Berenbaum and Robinson plan to carry on their detective work without additional funding. “It’s a mystery,” Berenbaum says. “We can’t sit down with the patients and ask them how they’re feeling. It makes it that much more challenging.”

Freelance writer C.D. Stelzer wrote about Amtrak service in central Illinois, “On the right track,” in the Jan. 25 issue of Illinois Times.


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