Researchers have identified four new viruses that infect healthy honeybees, potential clues that may help them better understand why colonies are dying.
Two of the discovered viruses, named Lake Sinai virus strains 1 & 2, were found to replicate in bees, according to the paper published today in the journal PLoS One. Over the 10-month study, the researchers also found that six common honeybee viruses were most abundant during summer months and that healthy bees carried fungi and bacteria, as well as mites.
Today’s study is one of the first to pinpoint viruses and other pathogens present in healthy colonies over time, adding key information to the understanding of honeybee health, said Christi Heintz, executive director of Project Apis m., a nonprofit research group of the beekeeping and agricultural industries that funded the paper.
“We brought a quantitative view of what real migrating populations look like in terms of disease,” said Joseph DeRisi, the paper’s senior study author and a professor of biochemistry and biophysics at the University of California, San Francisco, in a statement. “You can’t begin to understand colony die-off without understanding what normal is.”
Honeybees are needed to pollinate 130 different crops, representing more than $15 billion each year, according to the U.S. Department of Agriculture. Fruit-pollinated products are found in items such as Haagen-Dazs ice cream from Minneapolis-based General Mills. Lip balm made by Burt’s Bees Inc., a unit of Oakland, California-based Clorox Co., contains wax from the honeycombs of beehives.
Since 2006, the honeybee population has fallen partially because of Colony Collapse Disorder, an unexplained syndrome that has killed billions of bees. A United Nations report in March said that honeybee-colony deaths worldwide may be the result of reasons as varied as a decline in flowering plant species to insecticides and air pollution.
Colony Collapse Disorder has no effective antidote. The disorder is characterized by a massive flight of bees that don’t return to their hives to die.
The researchers followed 20 colonies in a commercial beekeeping business as they were transported to pollinate crops from Mississippi to South Dakota and then to California.
Over the 10 months, the bees were exposed to antimicrobial treatments, transportation stress and different pollen and nectar sources, the authors wrote.
The molecular fingerprints of 431 bees were examined to determine what viruses and other pathogens they carried, said lead study co-author Michelle Flenniken, a postdoctoral scientist at the University of California, San Francisco. The four new viruses are added to 10 already known, she said.
Today’s study will lead to future research, said Heintz, with Project Apis m., based in Chico, California. Apis mellifera is a species of honey bee.
“We might isolate some of these viruses and then try to re-inoculate a colony to see if there is one or a combination of several that really bring a colony down,” Heintz said today in a telephone interview. “Are these pathogens working independently or in combination to bring a colony down? Now we just know that they’re there, which is a huge step because we didn’t know it before.”
Dennis vanEngelsdorp, a senior extension associate at the Pennsylvania State University in State College, said studies are needed to determine if the viruses and pathogens are harmful.
“It could be some of these organisms found were beneficial,” vanEngelsdorp, who was not an author on the paper, said today in an e-mail. “It is not clear to me that the new viruses were in fact bee viruses; they could have been plant viruses that were in the pollen that the tested bees ate.”