Web edition: May 7, 2010
For the fourth year in a row, about a third of honey bee hives in the United States have died off during the winter.
That’s an estimate of the proportion of managed colonies killed by all sorts of mishaps, from diseases and the dreaded Varroa mite, not to mention bad weather and just plain bad luck. The estimate comes from a preliminary release of data from phone and online surveys by the Apiary Inspectors of America and the U.S. Department of Agriculture.
As to what happened to honey bees last winter, beekeepers reported that bad weather played an unusually large role compared with previous years, says entomologist Dennis vanEngelsdorp of Penn State University in University Park..
And 28 percent of the 4,207 beekeepers who answered the survey reported that at least for some of their doomed hives, worker bees vanished abruptly. Rapid disappearance is one of the main signs of bees succumbing to what’s now called colony collapse disorder. Five percent survey respondents blamed the disorder as the main cause of their losses.
Remarkably, beekeepers have managed to sustain such a string of bad years and still meet the demands of farmers for rented hives — at least so far. Entomologist vanEngelsdorp attributes the achievement to beekeepers’ dedication: “It’s a love,” he says.
Beekeepers cope with winter losses by taking bees from a survivor hives and giving them each a queen from some other source, such as a commercial supplier. One survivor colony turns into two diminished ones, but with good care, both should grow again. The recovery process adds expense and stress, however, and timing gets tight because the biggest commercial pollination event of the year comes in very early spring, when almond growers in California hire roughly half the hives available in the United States to get the crop pollinated. Yet beekeepers have managed to bounce back each year and meet the almond growers’ demands, vanEngelsdorp says.
Winters have always been stressful for honeybees, but it wasn’t always this bad. Several decades ago beekeepers used to say somebody was doing something wrong if winter losses rose above 10 percent, vanEngelsdorp remembers. But when the parasitic Varroa mites infested the United States in the late 1980s, beekeeping became much more difficult. And now colony collapse disorder, first reported in the winter of 2006-2007, is adding to losses.
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