Monday, October 29, 2007

"Update on Colony Collapse Disorder"

It was a mystery that left scientists around the world buzzing for answers. Last year a mysterious and deadly plague silently worked its way through bee colonies, leaving millions of dead bees in its wake. The killer was coined as CCD or Colony Collapse Disorder. It had moved in suddenly and unexpectedly, and left so few clues, experts could not crack the case.

Luckily this past September, there was a big break in the case. A team of scientists led by the U.S. Department of Agriculture (USDA), Pennsylvania State University, The Pennsylvanis State Department of Agriculture and Columbia University linked CCD with a virus imported from Australia, IAPV or Israeli Acute Paralysis Virus. Over the past three years, genetic tests on bees collected from stricken colonies around the U.S. found the virus in 96 percent of bees from hives affected by Colony Collapse Disorder.

IAPV had not historically been present in U.S. bees. In fact, it was only discovered in Israel in 2004, the same year American beekeepers started importing packaged bees from Australia. "Before that, nobody knew to look for it," says Jeff Pettis of the United States Department of Agriculture's Bee Research Laboratory. "As people began to look for it, it was found in China, Australia and the U.S."

Though the discovery of IAPV was indeed a big break, the case of CCD was not closed. Scientists have much to learn about how IAPV affects colonies and how it may have brought on CCD. Future studies will tell researchers if they are dealing with just one strain of the virus or if there are other strains to look for. "Discovering the IAPV was a lead but not the end of the story. We're looking at IAPV as a marker. It's there. It's present in colonies but viruses by themselves are not known to be that dangerous," says Pettis. Pettis and other scientists believe that CCD is not caused by one single factor, but by a whole host of forces including pesticides, parasites, poor nutrition, and stress. Any of these may leave bees vulnerable to infection and make IAPV lethal. "We know all of those things have affected bees in the past," says Pettis. "We have to look at combinations of factors."

Researchers at Penn State University and the USDA are planning a complicated set of experiments where they stress bees in certain ways and evaluate the effect on their health. The tests will hopefully indicate whether IAPV causes CCD by itself or if it is triggered by other pathogens and stresses.

Some studies on IAPV have already brought positive news. Israeli researchers say there is a possibility that IAPV-resistant bees can be bred. A third of bees sampled in Israel have incorporated the virus into their genome. In experiments, almost 20% of these bees survived when injected with IAPV.

While the work is ongoing and answers are sought, until the government declares otherwise, the nation's borders remain open for bees. Packaged bees are being brought in from Australia, which has yet to report cases of CCD colonies. Though researchers are still searching for answers, they are considering whether stressors that disproportionately affect U.S. bees such as pesticides, poor nutrition or pests like varroa mites might trigger the virus, making it virulent.

Last year, imports from Australia and New Zealand made up only 5 percent of the bees needed just for almond pollination (though almond pollination represents half of our need for honeybee pollination services).

Case closed? Not yet; but at least the prime suspect is now in custody. In the meantime, beekeepers must take measures to keep bees as healthy as possible. The goal now is improved nutrition, reduced stress, and better overall health for bees...

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Growing flowers for bees... (the bees have been abuzz over the red salvia in my wildflower garden)

...Choose flowers that bloom successively over the spring, summer, and fall seasons such as coreopsis, Russian sage, or germander in order to provide pollen and nectar resources to the native bees of all seasons. If you're not sure what to choose, you can always check with a local garden center for their advice on "bee-friendly" florals. To improve bee visitation, the garden should contain large patches of like flowers planted in close proximity to one another. Diversity is a key factor in keeping bee gardens buzzing. Researchers have found that more bees will be drawn to gardens with ten or more species of attractive plants.

As you diversify your garden, keep part of it wild because bees prefer that to a manicured space. Go for a "planted by nature" effect rather than a perfectly pruned garden. Remember: bees don't discriminate between weeds and cultivated flowers, so let those dandelions grow...

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