Buzz of a problem

In normal times, David Hackenberg would begin trucking his 20 million honeybees from the almond orchards of California to the orange groves of Florida in the middle of March. Instead, after a month working the almond blossoms on the West Coast, his exhausted pollinators will get some rest and relaxation in the Georgia woods before the East Coast apple blossoms summon them to work once more in April.

These are not normal times for bees, or for commercial beekeepers, so Hackenberg's pollinators will skip the citrus gig to reduce their exposure to pesticides and get some rest. "Everybody is seeing (bee) losses this winter," said Hackenberg, of Lewisburg, Pennsylvania. "This was probably the worst year ever."

More than three years after beekeepers starting seeing the sudden disappearance of hive populations, scientists have yet to find the cause — let alone the fix — for a condition called colony collapse disorder (CCD). Meanwhile, the commercial beekeeping industry is struggling to provide pollination services to America's farmers. One third of food crops rely on insect pollination.

A recently published survey suggests that hive losses have stabilised around 30 per cent a year but that high figure is based on last winter's data. Anecdotally the losses have climbed this winter.

"I am very concerned about this year based on what we have seen in California and other parts" of the United States, said Jeffery Pettis, research leader for the Agricultural Research Service's honey bee laboratory in Beltsville, Maryland.

Hackenberg said he and other major commercial beekeepers have seen "50 per cent or better" losses since late autumn and in the winter, when bees typically are clustered in a warm and fuzzy ball within the hive. "We started seeing losses in late October, early November — and they just kept going through the middle of January," he said. Some of the losses will be made up by beekeepers splitting one strong hive into two weaker ones.

Eighty per cent of his afflicted hives showed signs of CCD, Hackenberg said. With the condition, foraging worker bees don't return to a hive even if a full brood is waiting to hatch. One theory is that the foragers, knowing they are sick, fly off to die rather than compromise the hive.

Scientists at first figured that they would identify a single virus or pest responsible for the collapse after the phenomenon surfaced in autumn 2006 and an early suspect was a bloodsucking parasite called the Varroa mite.

After three years of research, scientists think the cause is not a single factor but a cocktail of maladies that together weaken and sicken the bees. "We know CCD bees get all the pathogens causing the symptoms; it doesn't leave answered what's the underlying cause," said Dennis van Engelsdorp, Pennsylvania's acting state apiarist.

Environmental stress, including pesticides and the strain of being trucked across time zones and climates, may also be a factor. Poor nutrition may also contribute, a diet of corn syrup or the nutritionally inferior nectar or pollen of crops such as cranberry, cucumbers or melons. "I thought we could find the smoking gun, make a recommendation and save the industry, and we have not been able to do that," said Jerry Hayes of the Florida Department of Agriculture.

"We think there's a cumulative effect, and trying to point the finger to one particular thing is difficult," Pettis said. "But bee health is in really bad shape, and we need to understand why."

Until a decade ago or so, beekeepers earned most of their income from honey but the honey crop is no longer profitable. The globalisation of the market has depressed prices as the costs of hive management have increased. Beekeepers now rely on pollination fees for the bulk of their income. As bees have become sicker, beekeepers have had to take better care of them through feed and medication and poor beekeepers have gone out of business, so hives are now managed by fewer keepers. But even the most diligent beekeepers are up against it this winter.

"We have been losing bees and beekeepers in this country for 60 years and now we are at the point where almost half the colonies in the country are needed to pollinate almonds in California," van Engelsdorp said. "We are close to the margin" of a viable ratio of pollinators to crops, he said. "It's amazing to see how close we are to that line."