Empty hives

A big part of what we eat is at stake as experts struggle to stop alarming bee disappearances

April 30, 2007

Billions od commercially employed honeybees - vital to the production of nearly 100 food crops across North America -- have buzz off.

Beekeepers say their industrious workers have been vanishing mysteriously from stores, their developing offspring and a forlorn queen and her attendants.

There have been other such "colony collapses," or "dwindles," in past decades, experts say. But this one appears to be the most serious - in the number of abandoned hives, their coast-to-coast geography and their duration.

"Apparently, a lot of these beekeepers have lost between 30 percent to as high as 80 to 90 percent of their colonies," said University of Maryland entomologist Mike Raupp. "This is pretty serious business. It's a big deal."

Although big commercial bee operations have been hit hardest by what's been dubbed "Colony Collapse Disorder," or CCD, smaller players and hobbyists are not immune.

"Last fall, I noticed it," said A. Dean Burroughs, 69, who contracts out 150 hives to eight farms near Salisbury on Maryland's Eastern Shore. "I was bringing my bees in for the winter from the farms ... and I go into the hive and there are no bees there."

In fact, five of his 150 hives were empty.

Hive losses have become common since the arrival of invasive mites and viruses in the 1980s and 1990s, he said. "But usually, when they die out from a virus or an insecticide kill, the bees are clumped in front of the hive, dead," Burroughs explained.

This time, they simply vanished.

Bigger operators, who truck hives by the thousands from citrus groves in Florida to berry farms in Maine, have been alarmed by losses of up to 90 percent. These beekeepers play a critical role in the nation's agricultural productivity. The U.S. Department of Agriculture says a third of the nation's diet depends on insect pollinators.

By itself, California's $2 billion almond industry requires 1.3 million commercial bee colonies every year. That's about half the country's commercial bee supply. Bees are also vital to forage crops - the alfalfa, clover and other pasture grasses that grazing animals require.

Pollination fees are already increasing sharply because of rising demand, and significant bee losses could reduce crop yields and increase food prices.

Responding to the alarm, scientists from academia, state and federal agricultural agencies, private companies and even the Department of Defense have formed the Colony Collapse Working Group. After conferences last week in Beltsville, their investigators fanned out to tackle the scientific puzzle.

"Right now we probably have 15 or 20 different researchers - primary scientists" working on the issue, said Diana Cox-Foster, an entomology professor at Pennsylvania State University and co-director of the working group.

The formal relationship between bees and farmers dates back centuries. scientists say. Bees, birds, bats and other foraging species co-evolved with certain flowering plants. In exchange for sweet nectar, they carry the flowers' male pollen to female portions of the flower. That allows the plants to mix up the gene pool, produce fruits, vegetables, nuts, seeds - and the next generation.

The National Academy of Sciences reported in 2004 that populations of wild, native pollinators - especially bees, bumblebees, bats and hummingbirds - are in long-term decline. Life hasn't been easy for the descendants of the European bees the early colonists imported, either. There have been reports since the mid-1800s of periodic hive collapses.

The biggest blow came in the mid-1980s, when imported honeybees introduced a parasitic mite called Varroa destructor. The varroa mites feed on the bees at all stages of their development and may also spread a deadly virus. Imports also introduced a trachea mite that infests the bees' breathing tubes.

As the mite infestations became widespread, winter kill rates soared, and crop pollination plummeted.

David C. Morris of Laurel, a bee hobbyist for 23 years, recalled a major mite infestation in 1995-1996 that hit pumpkin farmers particularly hard. "Mites killed off half the bees, and people couldn't get pollination," he said.

He remembers one 40-acre farm that produced barely 10 pumpkins.

Beekeepers have been battling mites ever since, enlisting a variety of mite-fighting chemicals and better hive management - but with no ultimate victory.

The mites, with their pathogens and parasites, have also taken a long-term toll. Fifty years ago there were 26,000 bee colonies in Maryland. Today there are just 12,000.

All but a handful of beekeepers here are hobbyists, and the three commercial pollinators, including Burroughs, are small.

So far, CCD does not appear to be a significant new factor in Maryland, Fischer said. But everyone is now on the lookout for it - hoping for a quick diagnosis and cure.

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