Bees crawl all over my body. I sit in the mud of a road embankment, watching the throngs that have landed on my legs. At the peak of one knee, three worker bees stand in urgent conference, sniffing: They stroke one another rapidly with their antennae, which house their organs of smell.
All around them, their sisters tumble. Pairs of bees seize each other around their minuscule midsections and wrestle. Others go about their private business in the midst of the crowd, using their forelegs to groom their furry faces and long tongues.
I watch, calm and safe inside my borrowed beekeeper's gear: white coverall, veiled pith helmet, protective gauntlets. Just down the road, Jeff Anderson and his three assistants methodically pry the lid off each of hundreds of hive boxes to check the health of the colonies inside. As the day wears on and the March sunshine warms this little-used ranch road in California's Sierra foothills, more and more bees take flight.
Wild buckthorn bushes lining the road carry clusters of tiny white flowers, their anthers bright with pollen. Bees work the blossoms, packing the yellow grains into smooth depressions on their hind legs, specially designed to carry this fuel (pollen is a high-protein food) back to the hive. On their travels, they transfer pollen from plant to plant, flower to flower, fertilizing the blossoms and allowing them to set fruit. This ancient partnership of pollinator and plant is essential to life as we know it. One-third of the food we eat comes from crops that need animal pollinators, a role often filled by bees but sometimes by butterflies, beetles, birds, or bats. Bee-pollinated foods include squash, tomatoes, peppers, apples, and pears. Unfortunately, the honeybees surrounding me are members of a threatened tribe, whose loss would have a dire effect on farmers, not to mention everyone who eats fruits and vegetables.
Bees became the focus of Jeff Anderson's life 30 years ago when he married his wife, Christine, a beekeeper's daughter. He joined his father-in-law, Joe Tweedy, in the family business. Ever since, he's been shuttling a carefully tended stock of honeybees cross-country, following the bloom of crops from California's early spring fruit orchards to Minnesota's summer fields of clover. Anderson's grown son Jeremy, working beside him, represents the fourth generation of beekeepers in the family. Without the services of managed honeybees, provided by migratory beekeepers like the Andersons, billions of dollars' worth of crops across the United States would fail.
I join Anderson as he opens another hive. Inside, eight wooden frames hold honeycomb whose surface is crowded with bees, all in constant motion though there seems to be no room to move. Speaking with an upper-midwestern lilt -- Anderson grew up on a Minnesota dairy farm -- he points out the queen, about 30 percent larger than the thousands of her worker-bee daughters who feed, build, and clean the hive. One or two black drones, males whose only function in life is to mate with a queen, stroll among the busy workers.
As he moves through the bee yard, Anderson can tell at a glance how each colony is doing. If all is well, the frames of honeycomb will be thick with bees giving forth a contented hum. But sometimes half the frames are bare and the bees just don't sound right. Sometimes the ground beneath a hive box is covered with bee carcasses.
Since Anderson began, in 1976, raising healthy bees has become more and more difficult. In the 1980s, two non-native species of parasitic mite infested North American honeybees. One of the species, Varroa destructor, has proved especially deadly. Meanwhile, safe pastures where bees can forage without being poisoned by pesticides are becoming increasingly rare.
The domesticated European honeybee was introduced to North America 400 years ago by colonists at Jamestown and Williamsburg to provide their settlements with honey; few bees native to the continent produced enough honey to make harvesting viable. Since then, the honeybee has spread into every farmable corner of North America. The cultivation of honey is an age-old pursuit: To maximize its production, beekeepers in Egypt during the time of the pharaohs floated their hives down the Nile to areas of abundant bloom, with some success. Early American beekeepers also transported their colonies -- on buckboard wagons, Mississippi River steamboats, and trains -- also with mixed results; the hives could not always be moved at the right times, the wax in the honeycombs often melted, the worker bees were sometimes left behind while their homes drifted downriver. In the 1940s, when new interstate highways and reliable long-haul trucks made it practical, beekeepers began regularly migrating long distances with their hives, following the flow of nectar as crops bloomed with the changing seasons.
In the boom years following World War II, large swaths of natural habitat across the United States were devoured by suburban development and agriculture. Patches of wild woodland, shrubs, and flowers that had supported native bees dwindled. The common practices of modern agriculture -- the widespread use of pesticides and the tendency to wipe out every wild flowering plant in sight -- began to destroy the pollinators that make farming possible. Beekeepers, accustomed to paying farmers for the privilege of stationing their beehives on land with blooming crops, started to receive payment from farmers for their pollination services. Today, migratory beekeepers follow this trail of money back and forth across the country as pollination fees continue to rise.
The United States and Canada are home to at least 4,500 species of native bee, from the sleek, iridescent blue mason to the plump, lemon-yellow bumblebee. All are at risk. "Where we live in Minnesota," says Anderson, "the local farmers will let their second cutting of alfalfa or red clover bloom, to feed the bees. A number of those people will tell you that the native bees just aren't there anymore."
A NEW WEBSITE! blogs, more multimedia, and award-winning journalism – come join the conversation at www.onearth.org
Feature Story
The Vanishing
Page 2
With the accelerating decline of native bees, honeybees are becoming ever more critical to farmers. American agriculture is addicted to honeybees -- and in the past few years has begun to run short of them. Anderson's spring starts in February, when the almonds in California's Central Valley come into bloom. California has more than 580,000 acres planted in almonds, though commercial beekeepers living full-time in the state hold enough bee colonies to pollinate only about half that acreage.
In the spring of 2005, many of the migratory beekeepers who work the California almond bloom discovered that their colonies had suffered heavy losses during the winter. Across the country, about one-third of all commercial honeybee colonies died out. The result was a pollinator panic in the Central Valley. Fees for renting beehives shot up from about $48 to as much as $140 per colony, a previously unheard-of amount. Beekeepers traveled from as far away as Florida and North Carolina to service California's almond groves. For the first time in 50 years, U.S. borders were opened to honeybees from New Zealand and Australia. The fate of a $1.2 billion crop -- more than half of all almond production worldwide -- rested on the slender back of the embattled honeybee.
Many bee experts assumed varroa mites were a major cause of the severe die-off in the winter of 2005. Yet when researchers from the U.S. Department of Agriculture (USDA) Bee Research Laboratory in Beltsville, Maryland, traveled to Oakdale, California, where Anderson and a number of his fellow beekeepers spend winter and spring, they could find no correlation between the level of varroa mite infestation and the health of bee colonies. "We couldn't pin the blame for the die-off on any single cause," says Jeff Pettis, a research entomologist at the lab.
Anderson has his own ideas about what caused the almond pollination crisis, and what is most responsible for wiping out honeybees across the United States. "Varroa is a bit of a red herring," he says. "One of the biggest problems is irresponsible use of pesticides and the failure of regulators to enforce the rules meant to protect bees from poisoning."
Over the past few years, Anderson has become a reluctant expert on one particular pesticide, Sevin, and the quirks of the system meant to govern its use. In the summer of 1998, Anderson's hives were stationed on farmland next to hybrid poplar groves managed by the Minnesota Department of Natural Resources and the International Paper Company. Both sprayed the trees with Sevin to control infestations of the cottonwood leaf beetle, which damages poplars. Soon after, Anderson's bees began to die. He videotaped sick ones as they lay twitching, just outside their hive boxes, in the throes of nerve poisoning from the insecticide. The poisonings would continue long after a Sevin application, he says, because worker bees carried contaminated pollen back to the hive, where it affected the colony for months. More than 50 percent of his bees died.
"I can't comment on the specifics of Anderson's case," says Pettis, "but I do know that Sevin and honeybees do not mix. What he purports could certainly happen. If the bees are storing Sevin in the pollen, when they get to California and feed on it over the winter, it's going to be as toxic as it was when they first picked it up."
In 2001, Anderson and two neighboring beekeepers filed a lawsuit against the Minnesota Department of Natural Resources and International Paper seeking $2 million in damages. Anderson has found himself enmeshed in the strange world of pesticide law. He's learned to speak fluent pesticide legalese, committed to memory whole sections of FIFRA (the Federal Insecticide, Fungicide, and Rodenticide Act), and has become both cynical and stubbornly hopeful about the state of pesticide regulation in the United States. "The law is not broke," he says. "It's the lack of enforcement that's the problem."
A district court judge initially dismissed Anderson's suit. But in January 2005, the Minnesota Supreme Court breathed new hope into the beekeepers' case, noting that by allowing the use of Sevin, Minnesota state policy seemed to conflict with the federally mandated bee caution on the pesticide label, which states that the chemical is highly toxic to bees and warns, "Do not apply this product . . . to blooming crops or weeds if bees are foraging in the treatment area."
The latest court decision makes it possible for the lawsuit to go forward, but Anderson is still hoping for the case to be heard by a jury. The Minnesota Department of Natural Resources reached an out-of-court settlement with the beekeepers, in which it agreed to stop using Sevin, but International Paper continues to spray its more than 30,000 acres of poplars, which it harvests to manufacture paper pulp and fiberboard.
Unable to keep their hives healthy near the sprayed poplar groves, many beekeepers have moved away from Eagle Bend, Minnesota, where Anderson and his family have summered for decades. After a particularly disastrous series of die-offs in 2002, Anderson moved his hives to fields far from the sprayed poplars, and he now makes a long commute every time he works his bees in the summer. Since the move, the survival rate of his colonies has improved. Even last spring, when many of his colleagues suffered major losses, his colonies did relatively well. He sees this as confirmation that Sevin contamination is finally fading among his hives.
"I'm standing my ground," Anderson says. "If I pick up and move to another state, they'll just blast me with some other pesticide." He's familiar with the chemical disasters that struck beekeepers in Nebraska, Colorado, North Carolina, and Washington in the 1990s, when the insecticide Penncap-M became popular as a defense against corn rootworm, the larval form of a beetle that attacks the roots of corn plants. Penncap-M, a microencapsulated form of methyl parathion, could have been designed as the ultimate bee-killing weapon: a highly toxic, long-lived nerve poison enclosed in tiny, pollen-size beads. Foraging bees packed these pellets into their pollen sacs along with the real thing and carried them home, devastating their colonies.
Corn is easily wind-pollinated, so although bees gather corn pollen, growers don't need them. They see Penncap-M as the cheapest, most efficient answer to their rootworm problem, and its impact on bees has not convinced them to give it up. Significant honeybee die-offs due to Penncap-M are on the wane, but not because of pesticide regulation. Beekeepers who weathered major losses from Penncap-M now keep their hives far from anywhere the pesticide is used. Some beekeepers, however, were driven out of business by massive bee kills, becoming statistics in the long-term decline of commercial honeybees in this country. In the late 1940s, U.S. beekeepers held about 5 million colonies; gradually that number has dropped to about 2.3 million.
At the compound in Oakdale, California, where Anderson and his family spend the winter, his two youngest children, dressed in Confederate gray, are staging a very small-scale reenactment of a Civil War battle beneath tall valley oaks. Anderson walks with me to my car as I get ready to leave. A wry smile creases his face, ruddy from long days out in the weather. "You know," he says, "it's a catch-22. If my bees are nowhere near the poplars anymore, then International Paper can claim it's OK to spray Sevin. So those bee pastures, which we've depended on for so many years, may be lost forever."
The decline of honeybee populations has brought the agricultural community to the brink of a pollination crisis. The best hope for the long-term survival of many American farmers may be the revival of native bees. Yet they, like their domesticated cousins, face some daunting obstacles.
California's Central Valley, one of the most productive agricultural regions in the West, is a forbidding wasteland for native bees. Endless acres of orchards, fields, and suburban ranchettes are kept clear of anything that's perceived as a weed -- and that includes wild shrubs like ceanothus, buckthorn, and redbud, whose flowers are rich pollen sources for bees in early spring.
A few dozen honeybees patrol the dazzling purple-pink blossoms of a redbud growing in a small arboretum, tucked along the banks of a creek that crosses the campus of the University of California, Davis. Flying among them is a single native bumblebee, insulated on this chill afternoon by her thick lemon-yellow fur. She's loading pollen onto her corbiculae, hair-rimmed, basket-like structures on her back legs that hold the bright grains for transport to her colony.
Robbin Thorp waves his net like a magic wand and extracts the bee from the tangle of twigs where she's been foraging. With expert movements, he guides her into the pointed end of the net and pops her, unhurt, into a glass tube where I can study her up close. Thorp, an emeritus professor of entomology, has devoted a long career to native bees. As a graduate student in the 1950s he identified five species previously unknown to science. Now, though his beard has turned snow white and he's been officially retired for a decade, Thorp continues to spend time in the field. But these days he's more likely to be tracking the decline and disappearance of once-abundant bees.
When Claire Kremen, a conservation biologist at the University of California, Berkeley, set out in 1999 to study the contribution of native bees to crop pollination in the Central Valley, she called on Thorp to train her research crew in the art of identifying bees on the wing. Under his tutelage they learned to tell the common local species of bumblebees apart, to recognize the narrow yellow-black striping and streamlined shape of a squash bee and the blue-green iridescence of a metallic bee.
Kremen's study focused on watermelon, because the blossoms need a lot of pollen -- about 1,000 grains per flower -- to produce a marketable fruit. If native bees can do well pollinating watermelon, they're likely to succeed with just about any other crop. She and her field assistants spent long summer days walking transects in watermelon fields, counting the numbers of each kind of native bee they saw working the flowers. Kremen's research, among the first to examine the status of native bees on agricultural land in the United States, produced dramatic results.
Farms with no nearby oak woodland or chaparral have too few native bees to succeed without the services of rented honeybees. But those near remnants of wild habitat host native bees of many species, in numbers high enough to pollinate even a demanding crop like watermelon. The farms that fell into this category were all organic operations set on smaller plots of land tucked into hillsides where native vegetation survives. By contrast, conventional farms not only use a variety of pesticides but are set in the midst of the Central Valley's hostile landscape.
"Pollination is a valuable service that we're destroying through our land management practices," says Kremen. But she points out that there are many ways conventional farming could change to support bees. One is to grow cover crops like rye and clover, which aren't harvested but instead plowed under to enrich the soil after they've flowered. Farmers could also use roadsides and ditches to restore native plants and create bee-nesting areas. They could reduce their use of pesticides or apply them at night, when bees aren't flying. Growers ought to do these things, Kremen believes, not out of selfless concern for threatened bees but because, in the end, it will protect their own bottom line. Since honeybees -- which now pollinate up to $14 billion worth of crops annually in this country -- are in steep decline, native bees are needed as a backup. The costs of managing bee habitat could be offset by reductions in the amount a farmer spends on renting honeybees, a cost that continues to increase for many crops. In 1999, for example, U.S. plum growers paid about $6.4 million for honeybee pollination.
Kremen was able to discover which species are most efficient by "interviewing the bees." This involved shrouding watermelon blossoms in bee-proof veils, uncovering them just long enough for a single bee to visit, and measuring the pollen left behind. Some of the natives, including two species of bumblebee and the squash bee, do a far better job of delivering pollen than do honeybees. Kremen also noted that over the two years of her study, the numbers of native bees shifted. In one year, a few types of high-efficiency bees accounted for most of the pollination. The next, many species contributed. That finding argues for the need to maintain a diversity of bees, leaving enough flexibility for crops and their pollinators to survive shifting conditions.
"We need to have a balanced pollinator portfolio, and we don't right now," says Stephen Buchmann, founder of The Bee Works, an environmental consulting firm specializing in pollination issues. "Just like in investing, we need to have a balance between short- and long-term risk."
Buchmann acknowledges that honeybees are indispensable to modern agriculture, but he points out that they can't carry the burden of crop pollination alone. He believes that protection of native bee habitat and active management of native species must also be part of the solution to the pollinator shortage. The rise and fall of the alkali bee, recounted in his book The Forgotten Pollinators, coauthored with Gary Nabhan, illustrates both the great agricultural potential of native bees and the threats they face.
The native alkali bee, a solitary creature that digs its nest near seeps in the alkaline soil of western deserts, is a champion pollinator of alfalfa (alfalfa hay is a staple food for dairy cattle and other livestock). The plant's flowers are typical of legumes: The sexual parts are held under tension, and to gather pollen a bee must trigger their release, receiving a smack on the head in the process. Alkali bees, which are particularly well suited to pollinate wild legumes like lotus and locoweed, are unfazed by this experience. European honeybees avoid it.
In the 1950s, alfalfa farmers in Nevada, Idaho, California, eastern Oregon, and Washington began to create artificial nesting areas for alkali bees, seeding them with plugs of soil from natural bee beds. One result was a lasting expansion of the alkali bee population in the places where humans needed them most. Another was a boom in alfalfa seed production in the American West. With alkali bees working the blossoms, the yield of seed used to replant hay fields skyrocketed.
Then, during the 1970s, managed alkali bee populations began to crash. Some alfalfa growers believe that a shift in pesticide use on neighboring crops did the bees in: Alkali bees will fly a mile or more in a day and forage on a variety of flowers, so they could easily have picked up poisons beyond the alfalfa fields. Or perhaps alfalfa farmers' own use of insecticides to combat a common pest, the lygus bug, destroyed the bees. In any case, the lion's share of the U.S. alfalfa crop, worth $5 billion a year, now depends on the alfalfa leafcutter bee, a nonnative species. Canadian farmers produce the bees, which feed on the pollen of canola and alfalfa, and sell loose cocoons by the gallon to growers in the United States. About $30 million worth of leafcutter bees are purchased each year; efforts to raise them in this country sputtered when infectious diseases wiped out the young bees. One such disease, chalkbrood, is now hitting the Canadian industry. A collapse in the leafcutter bee population could wipe out most alfalfa production in the United States, with serious consequences for the dairy industry.
The alkali bee is not the only native with impressive agricultural talents. The blue orchard bee, an opalescent creature native to the western United States, can pollinate almonds, cherries, and other orchard crops far more efficiently than honeybees can. Since it's adapted to local conditions, it's hardier, too: It will fly at lower temperatures than the honeybee and work blossoms in the rain. In a four-year experiment at a cherry orchard in Utah, William Kemp of the USDA Northern Crop Science Laboratory in Fargo, North Dakota, found that fruit production doubled when blue orchard bees (affectionately known to bee fanatics as BOBs) were used in place of honeybees. Kemp and his colleagues are encouraging fruit growers to nurture BOBs on their land. A few entrepreneurs have begun to trap the bees in the wild and rent them to growers.
There can be risks in the commercialization of native species, however. When alfalfa farmers began to manage for alkali bees on their land, they were working within the bee's natural range. But when tomato growers discovered the power of bumblebees to increase their yields, the bees were treated like any other product in a globalized economy and were shipped from continent to continent, with disastrous consequences.
For decades, hothouse farmers used electric vibrators to pollinate their tomatoes, an expensive and sometimes labor-intensive process. The flowers of certain crops -- notably tomatoes and members of the tomato family including potatoes, eggplant, and peppers -- hold their pollen inside chambers with tiny openings. The grains are trapped, like salt in a saltshaker. For a bee to release the pollen, she must vibrate her body like a violin string, grasping the flower while using rapid-fire contractions of her flight muscles to produce a high-intensity buzz. Honeybees don't do this.
But bumblebees are masters of buzz pollination -- a fact that farmers did not think to exploit until Roland de Jog, a Belgian medical doctor and bumblebee enthusiast, came up with the idea of placing his pet bees among a friend's tomatoes. The experiment was a huge success, and in 1987 de Jog founded Biobest, a company based in Westerlo, Belgium, that rears bumblebees and sells them to tomato growers in both Europe and the United States.
In the early 1990s, a U.S. breeder shipped American bumblebee queens to Biobest. The resulting colonies were shipped back to the United States, carrying with them an infectious disease to which native American bees had no resistance. "That exotic disease wiped out Bombus occidentalis," says Robbin Thorp, who has documented the disappearance of the species, which was once commonly found everywhere from central California to British Columbia. The USDA restricts the use of bumblebees shipped from Europe, in an effort to keep them inside greenhouses and out of the wild. But the bees still escape, carrying infectious diseases with them. A recent study in Canada showed that levels of infectious disease are much higher among wild bumblebees near tomato greenhouses. Mistakes like these could cause other species to follow B. occidentalis into oblivion.
n the long run, our own survival is deeply entwined with the lives of bees. And the bees' survival depends on the ways we manage not only rural farms, but also city parks and gardens and the landscape of suburban America, where native bees can survive in even small patches of habitat, such as native shrubs and plants. "There's an economic benefit to taking care of native bees," says Thorp. "But until people understand this, they won't spend time and effort on it."
Full Belly Farm, an organic operation where Kremen and her research team spent five years studying pollination, has begun to plant hedgerows of native shrubbery to nurture native bees. Other organic farmers in California's Yolo and Solano counties are following Full Belly's lead. Convincing conventional farmers that it's worth their while to do the same -- and to limit their use of pesticides as well -- poses a greater challenge, requiring major shifts in attitude and focus.
In his time, Thorp has seen many acres of native bee habitat vanish beneath plows and under pavement. Some of the data he gathered as a young man are now being used by a new generation of scientists as a baseline to measure the bee diversity that has been lost. Yet Thorp is not a pessimist. He describes a recent trip to the southern Central Valley, a place now dominated by vast fields of cotton, safflower, and alfalfa. For much of the year -- when the crops are not blooming -- these fields, devoid of flowering weeds, are about as welcoming to pollinators as the surface of the moon. Yet in cracks in the ground, in the ditches between crop rows, Thorp found what he had not dared to hope for: the nests of wild sweat bees.
No comments:
Post a Comment