Silent spring: what's happening to honey bees?

On a warm April morning, John Keeley's farm southeast of Portland, Oregon is lively with sound. His two dogs bark as they dash around the farm's dark wooden buildings; his sheep and lambs bleat as they waddle across rolling green fields. Birds twitter, and turkeys cackle. But the white boxes scattered around his 85 acres are mostly silent.

Keeley is a retired civil engineer who keeps bees to pollinate his orchards: cherries, apples, peaches, plums and chestnuts. "You can easily double your fruit-tree production just with bees" he says. But this winter, he lost 12 of his 14 honeybee hives. "In February, they seemed to be doing all right," he says. "By March, they were all dead."

He picks up a hive frame still thick with honey along the edges and gently puts his thumb and forefinger around a dead bee, curled stiff against the honeycomb. "See, they had plenty of honey to eat," he says. "I don't know what killed them."

Like most beekeepers these days, Keeley doses his hives with a variety of treatments to keep the bees free of affliction: disease, mites and invasions by marauding animals such as skunks. But honey-bee populations are plummeting nevertheless. "We're losing between 40 and 60 percent of our bee population annually in this country," says Gordon Wardell, an entomologist based in Tucson. "The bee industry is right on the edge."

Honey bees pollinate more than 90 cultivated crops, including avocadoes, cu cumbers, watermelons, citrus fruit and, notably, almonds; California's almond industry alone needs about half the country's 2.5 million commercial hives for pollination every year. Honey bees are responsible for more than $20 billion in annual pollination value and one-third of the food we eat, from vegetables to oils to meat from animals that graze on pollinated forage.

Managed honey bees, such as Keeley's, aren't the only pollinators in the air. According to Michael Burgett, an entomologist based in Corvallis, Oregon, in the Pacific Northwest alone there are some 900 species of native bees. And plenty of plants, such as tomatoes, get along fine with mere wind pollination. But because modern agriculture demands high yields from densely planted crops, they need modern commercial honey bees, in massive quantities, in order to seize the day when the bloom is peaking.

As a result, professional beekeepers have become migrants, trucking their bees along interstates. It's an artificial setup, made more so by the fact that the bees are descended from imports--European honey bees brought over to the New World in the 16th century.

For hundreds of years, the docile European honey bee flourished in North America, with some estimates putting their escaped, wild population at 10 to 20 colonies per square mile. But in recent decades, feral European honey bees have practically vanished, their numbers dropping by more than 90 percent, while the population of managed honey bees has dropped by two-thirds.

Because of their size, Burgett points out, bees are very easy to smuggle across international borders, bringing unseen diseases and parasites with them. And of course, bees travel quite efficiently on their own. Bees, it seems, may be too popular for their own good, their density and mobility combining to kill them.

Wardell describes an imaginary bee yard, with 25 to 50 colonies close together. Mites hit one hive and weaken its bees; nearby bees take notice and come over to rob their suffering brethren of their honey. And the mites hitch a ride to a new home. "If the colonies were spread out two to three miles apart, as in nature, any mites that killed off a colony would have died out or come into balance with the bees," Wardell says.

The European honey bee has long battled a variety of diseases, including the smelly, aptly named foulbrood. A nationwide ban on bee imports managed to keep out tracheal mites, another traditional foe of the European bee, until 1984. But it was the 1987 arrival of the Asian varroa mite that really did damage.

"Every honey bee, with the exception of the European honey bee, has a mite that attacks the larval stage," says Burgett. "The varroa mite was very happy to switch hosts. In a European honey-bee colony, it's a death sentence."

Keeley thinks his bees might have had mites, which survived his fall chemical treatments and weakened his bees over the winter. "And then, I presume, a virus came in and knocked them off," he says.

The three main categories of chemical treatments available today are pyrethroids (such as Apistan), organophosphates (such as Coumaphos), and essential oils (such as menthol and thymol). Beekeepers, unaccustomed to applying complex chemicals to their hives, have tended to overuse or misapply the products, and mites develop resistance. Today, chemicals are typically recommended as part of an integrated pest management (IPM) approach to beekeeping.

Researchers are looking not just at chemicals but at genetic, nutritional and physical ways of managing bees. Techniques underway include breeding mite-resistant bees, feeding them supplemental protein to help them get through the winter, redesigning hives so that mites are crowded out or knocked off and caging honey-bee queens briefly to stop the mite's life cycle. Even powdered sugar has become a popular treatment; varroa mites tend to simply fall off the dusted bees.

"The ultimate solution is genetic" says Burgett, who's working to find mite-tolerant bees. "But that takes a lot of time. It would develop on its own if we absolutely forbid the movement of bees in the U.S., but we can't do that because of the huge pollination requirements."

The federal government is currently funding the Honey Bee Genome Project, mapping the bee's entire genome. In the long run, having a genetic guide to the honey bee will probably help save it. For now, scientists are looking at other options, such as the Africanized honey bee (a/k/a "killer bees"), an aggressive insect that arrived in the U.S. in 1990 and is known to be resistant to varroa mites.

And despite all the problems, Burgett says there's never been a better time to be a beekeeper. Those who stayed in the business are seeing record prices for honey and hive rentals.

Not far from Keeley's farm is a large commercial beekeeping operation, Foothills Honey, which hosts an annual spring Bee Day for Oregon beekeepers. Dozens of beekeepers draped in black veils and white suits gather around white boxes in green fields, listening to lectures on bee management. This year at Foothills, the bees are everywhere, loose dark clouds against a blue sky.

Another Corvallis-based entomologist, Lynn Royce, is lecturing about the many complicated methods of keeping bees healthy. "I think we brought this on ourselves," she says, plucking a drone from a hive with her bare hands. "But I've finally learned, after years and years, that you can be tough on bees." CONTACT: American Beekeeping Federation, [phone], www.abfnet.org; American Honey Producers Association, [phone], www.americanhoney producers.org.--Caroline Cummins