bee, colony collapse disorder

Bee Gene Damage May Be Cause of Colony Collapse Disorder

August 27, 2009 08:00 AM
by Haley A. Lovett
According to a new study, simultaneous infection with multiple viruses might be the reason why bee colonies have been mysteriously dying off over the last few years.

Decoded Bee Genome Helps Scientists Study CCD

Entomologist May Berenbaum and a group of scientists have identified differences in the genetic material found in the guts of bees from colonies affected by CCD, and those not affected. In a study published in the Proceedings of the National Academy of Sciences, Berenbaum and her colleagues found that the bees from CCD-affected hives had genetic damage that they thought was caused not by pesticides, as has often been blamed for CCD, but potentially by infection with multiple viruses at one time. The weakened genes would make the bees unable to combat additional infection or toxins.

The multiple virus theory may explain why scientists have been unable to pinpoint one exact cause of CCD.

According to Bryan Walsh of Time magazine, Berenbaum’s study would not have been possible had the genome of bees not been decoded (only a few animals’ genomes have been decoded). The decoded genome allows scientists to compare all of a bee’s genes at once to look for similarities and differences. Walsh points out that the reason the researchers look at the genes from the gut of the bee is because that is where immune responses take place and where pesticides are processed.

How Fungus Footbaths Might Save the Bee Populations

Now that having multiple viral infections has been pinpointed as a potential factor in CCD, scientists must look for ways to prevent infection. As early as a year ago, researchers had wondered if the varroa mite parasite could be to blame for the sudden deaths of so many bees. Now, knowing the common genetic damage found in CCD bees, the infections carried by the mite are of particular concern to scientists.

Varroa mites are now controlled using pesticides, but scientists are looking for non-chemical ways to rid the bees of the mites. Certain strains of fungi can kill the mite, and scientists have experimented with methods to deliver the fungi to the hives, including using sprays, powders and even a footbath of fungus to get bees to bring it into the hive.

Background: Colony collapse disorder

In 2007, researchers began studying bee populations closely, looking for information about why there seemed to be fewer bees. In each of the first two years that bee populations were recorded, losses of nearly one third of the bee population were observed.

In the beginning there were many theories about the potential cause of the sudden abandonment of hives around the world (since dubbed colony collapse disorder). Some blamed cell phones, genetically modified crops, pesticides, fungi or other infection.

Whatever the cause, CCD is a serious concern for scientists and others, as bees are vital for plant pollination. In the U.S. bees are relied on to pollinate much of the food supply, and play a key role in the crop industry.

Berenbaum, the head researcher of the latest bee study, told Walsh that we may have seen the worse of CCD and that the disorder might be on the decline. “The most vulnerable populations might have already crashed,” Berenbaum said.

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