Give Bees a Chance—The Mystery of Colony Collapse Disorder
The honey bees arrived at 1600 Pennsylvania Avenue in March, installed on the South Lawn by White House carpenter and beekeeper Charlie Brandts. In April, much to the amusement of the press, they swarmed. Brandts calmly boxed the errant queen and returned the girls to work; he collected the first batch of honey in June. Meanwhile, a bipartisan group of 20 senators requested that the Agriculture Appropriations Subcommittee allocate $20 million in fiscal year 2010 for pollinator research projects, as authorized by the 2008 Farm Bill. Senator Barbara Boxer explained, "These funds will increase the resilience and security of our farming systems by supporting vital research into colony collapse disorder (CCD) in managed honey bees and native bee ecology."
Helping the honey bees is hip. Urban beekeeping collectives are springing up, green buildings are installing hives to signal their commitment to the environment, and even businesses like H‰agen-Dazs are financing pollinator research.
If you're wondering why there's such commotion, imagine cherry vanilla ice cream without the cherries. While some crops are pollinated by wind, many of the foods we eat require an intermediary pollinator. Without pollinators, we could say good-bye to fruits like cherries and blueberries; the fruits we call vegetables, like tomatoes, cucumbers, peppers, and squash; and seeds like coffee and almonds. In the United States, managed honey bees pollinate over 100 commercial crops worth over $15 billion. And these bees are dying.
Migrant Worker Bees
Bees are age-old pollinators that have coevolved in complex association with plants. And their relationship with humans is nothing new. Of over 20,000 known species of bees, only 7 species, all of the genus Apis, are known to produce enough excess honey for humans to harvest—hence their common name, honey bee. Humans have gathered honey for over 10,000 years, and both Apis cerana (Asian honey bee) and A. mellifera (European honey bee) are commonly domesticated. There are no extant honey bees native to the Americas, but they have been naturalized here since they were brought over by Europeans. In addition to making honey and beeswax, honey bees are employed as commercial pollinators. Their hives are stacked on flatbeds and trucked to California's almond crops, to Florida's remaining citrus groves, to Maine's blueberries, and down South to cotton fields. In fact, today the honey bee's primary commercial value is as a crop pollinator.
Beekeeping for managed pollination is a fairly new industry. In the 1990s, faced with inexpensive honey imports and the expanding industrial-agricultural system, beekeepers found themselves becoming long-distance truckers. This shift took only a generation; on my grandmother's farm, native pollinators and a homestead hive or two did the job. Beekeepers paid (in honey) to keep their hives on the family's land. But as any old farmer will tell you (including Grandma), things sure have changed! Populations of native flower-visiting insects have dropped in disturbed areas, and the trend toward large acreages of specialized crops that need pollination to set fruit requires vastly more pollinators than would naturally be present. The most dramatic example of pollination-for-hire takes place from February to mid-March in California, producer of 80 percent of the world's almonds. Almond growers rely on honey bees from as far as the other side of North America—and sometimes even overseas—to pollinate 700,000 acres of crops. While this soaring demand for hives sounds like a good thing for bees, the artificial conditions under which these travelling pollinators live may make this practice unsustainable.
Colony Collapse Disorder
In November 2006, beekeepers in the United States and Europe began to notice something strange happening to their hives. The bees were vanishing. And the empty hives, normally a bonanza for honey-hungry critters, remained untouched. When some beekeepers lost up to 90 percent of their bees and the pollination of spring crops was jeopardized, colony collapse disorder made headlines.
New World Natives: Bumble Bees
Bumble bees' oafish reputation comes from their large size, which at first glance would seem to preclude them from flight. Native to North America, these fuzzy bees (Bombus species) do not produce surplus honey, but they remain important pollinators for both wild and cultivated plants.
Bees are critical agents for members of the nightshade family (Solanaceae), like the tomato, a self-fertile plant that requires vibrations in order to be pollinated. A bumble bee, seeking nectar, grasps blossom filaments with its limbs and mouth while it vibrates its wings for stability. When the bee's buzzing reaches the correct frequency, the tomato flower's stamens release pollen grains. Other plants that require "buzz pollination" include blueberries, cranberries, and other nightshades such as peppers, potatoes, and eggplants. Many greenhouses rely on bumble bees to pollinate these crops.
The recent drop in exotic honey bee populations may seem like a boon for wild pollinators, but studies suggest many American bumble bees are imperiled as well. A report by the Xerces Society found significant decline in three formerly common bumble bee species, which it attributes to pressures including the destruction of habitat and the spread of pests and diseases by the commercial bumble bee industry.
CCD is a mysterious syndrome characterized by adult bees abandoning the hive, leaving behind their brood and food stores that are left undisturbed by other bees and hive pests such as wax moth. There is little or no evidence of dead bees; in some cases, the queen and a small group of survivors remain in the collapsed hive. Early signs of trouble include a workforce that appears to be made up of young bees and is insufficiently large to maintain the brood; the queen is present, appears healthy, and is usually still laying eggs, but there is little evidence of foraging populations; and the cluster is reluctant to consume food provided by the beekeeper, such as sugar syrup and protein supplements.
Initial explanations for the disorder ranged from the bizarre, like the theory that radiation from cell phone towers was causing the bees' navigation systems to go haywire, to the plausible, including the suspicion that genetically modified crops like corn were damaging bee health. (Areas with GM crops showed no direct correlation to bee colonies with CCD.)
Other suspected culprits included the newly discovered Israeli acute paralysis virus (IAPV), although its symptoms didn't correlate to CCD and the virus had been present in bees before 2006. Nosema ceranae, a fungus that attacks the digestive system of bees, eventually starving the bee, was also evaluated. Nosema was especially compelling because it fit the symptoms of CCD particularly well: Infected bees would fly out into the field and starve, unable to digest their food. However, American colonies infected by N. ceranae that were treated with the antibiotic fumagillin bounced back from the fungus and yet still experienced CCD.
Intensive research into the pathology of CCD indicates that no single disease is plaguing the honey bee. Instead, data point to all of them. Bees from CCD hives tested positive for a combination of 14 different viruses. And even bees tested from hives apparently unaffected by CCD revealed the presence of numerous viruses.
Working honey bees' immune systems are assaulted from all sides—by pathogens, stress, and poor diet. Eating a single type of pollen for weeks on end deprives the honey bee of important vital nutrients. To keep colonies going, beekeepers feed them corn syrup solutions laced with antibiotics, which destroy both the "bad guys" and the ten or so beneficial bacteria species found naturally in bees, their first line of defense against unwanted pathogens.
Some honey bees suffer from PMS: parasitic mite syndrome. The varroa mite, first noted in America's honey bees in 1987, has caused drastic damage to colonies. The mite sneaks into a larval cell and waits until a worker bee caps the cell, then lays eggs, which hatch and feed on bee pupae. The mites live off the blood of the pupa, robbing the developing bee of precious nutrients and leaving it malformed and highly susceptible to disease as an adult.
Honey bees are also exposed to the chemicals and pesticides used on the crops they pollinate, including a new class of pesticides known as neonicotinoids that was first introduced about 15 years ago. Neonictinoids, such as imidacloprid, which is used extensively in the U.S., mimic nicotine, a natural defense against insects. The products act as nerve poisons, causing disorientation, memory loss, spasms, paralysis, and death. Both France and Germany have banned imidacloprid because it was implicated in honey bee colony collapses.
A Continuing Concern
Currently, damage to commercial hives appears to be lessening. Surveys of U.S. beekeepers conducted by the Apiary Inspectors of America and USDA-ARS Beltsville Honey Bee Lab show a 28.6 percent winter colony loss in 2008ñ2009, compared to a 35.8 percent loss the prior year. According to Rowan Jacobsen, author of Fruitless Fall: The Collapse of the Honey Bee and the Coming Agricultural Crisis (2008), it's because "many beekeepers woke up and started paying more attention to the well-being of their bees: They made more of an effort to keep them away from imidacloprid, they treated much more extensively for nosema infection, and they fed their bees pollen patties to keep their protein levels up."
Some reports have pointed to historical cycles of bee population die-offs and suggested that the situation may right itself. Others are not so hopeful. Says apiculturist Eric Mussen, an entomologist at UC Davis, "Despite the current inability of researchers to isolate and identify one or more novel pathogens associated with the losses, observations in the field suggest that the malady is contagious. Compared to similar unexplained large losses of colonies in the past, this continuing problem has persisted longer and is still exacting a severe financial toll on beekeeping operations."
The 2007 losses were a global wake-up call for beekeepers, many of whom lost over half their hives. But the lessons of CCD are just as important for farmers and their customers. In Fruitless Fall, Jacobsen points out that networks of organic, pesticide-free farms surrounded by patches of wild, native plants are not only good for honey bees, they also support indigenous bee colonies as well, dramatically cutting the need for pollinators-for-hire. This model would resemble the landscape of the farm my grandmother grew up on, which, although more modestly productive, may ultimately prove more sustainable than our current system of agriculture.
For more on honey bees, check out apiculture societies like the Mid-Atlantic Apiculture Research and Extension Consortium (maarec.cas.psu.edu).
Project Apis m. brings together beekeepers and farmers and funds research on managed honey bee colonies (projectapism.org).
The Xerces Society, named for the extinct butterfly Xerces blue, provides info on pollinators and other invertebrates (www.xerces.org).