Subscribe for 17¢ / day

The mysterious case of the missing honeybees might finally be solved.

Since 2006, billions of bees have flown from their hives and simply disappeared as part of a mysterious malady called Colony Collapse Disorder.

Until now, nobody knew why.

A research team, including University of Montana honeybee experts, may have uncovered the one-two punch that has been killing the bees.

Using high-tech U.S. Army analytical equipment, researchers discovered a previously unknown North American honeybee virus and a fungal pathogen in all of the samples of ground-up honeybees collected at hives afflicted by CCD from 2006 to 2009.

Neither pathogen was uncovered in samples from colonies without CCD from Montana and Australia.

The research was published Wednesday in PLoS ONE, a scientific journal found online at

While it's still too early to know for sure if these pathogens are the cause of the disorder, researchers are encouraged.

"We truly don't know if these two pathogens cause CCD or whether the colonies with CCD are more likely to succumb to these two pathogens," said UM biology research professor Jerry Bromenshenk. "It's a work in progress, but it may be the most important advance in the search for the cause of CCD in the previous three years."

Bromenshenk was among the first to document CCD when it appeared four years ago. He has been looking for its source ever since.


Like much good science, the path leading to discovery of the pathogens was a crooked one that began when Bromenshenk's team was struck by the fact that no other insect pests invaded the infected hives after the bees began to disappear.

Maybe, they thought, there was some kind of repellent being produced or perhaps there was a pesticide residual that was keeping the bugs at bay.

And so they began to look toward chemistry.

At about the same time, Dave Wick of BVS Inc. in Florence suggested the potential of a virus. Wick had a contact with the U.S. Army's Edgewood Chemical Biological Center at the Aberdeen Proving Grounds in Maryland.

The center had a liquid-chromatograph proteomics mass-spectrometry device capable of quantifying as many as 30,000 proteins in a single sample.

The researchers' sample of ground honeybees from all the CCD-infected hives revealed an insect iridescent virus, or IIV, and a fungal pathogen called Nosema ceranae.

The virus was similar to one reported in India 20 years ago, as well as a virus found in moths. Strains of it are virulent enough to once be considered a bio-pesticide for other nastier insect pests.

The virus afflicts the abdomens of bees. It's named iridescent because infected host tissues can take on a bluish-green or purplish hue.

With the pathogen, the bees ingest spores that allow the fungus to spread in the gut.

Either the virus or the fungus by itself may make bees sick, but together they might be too much for the insect to survive.

"From our data, there seems to be a correlation between the presence of these two pathogens together," said Robert Cramer, a Montana State University research partner and fungal pathologist. "We envision the bee gets an infection from one or the other, and this causes the immune system of the bee to get suppressed, which then allows the second infection to come in and more effectively cause disease."

The strain of virus they discovered had never been fully sequenced before.

"It's probably a variant or something new," Bromenshenk said.


It was different from most other bee viruses in another way, too.

Most viruses that attack bees are smaller, single strand RNA design. This iridescent virus was a larger double-stranded DNA.

"This is a fundamental difference that takes CCD research in a whole new direction," Bromenshenk said.

The discovery of the new virus was totally unexpected.

"When they told us that it was an iridescent virus, we all looked at each other," Bromenshenk said. "We didn't know what an iridescent virus was."

And so they turned to someone who did.

"Trevor Williams literally wrote the book on insect iridescent viruses," he said. "He turned out to be the consummate scientist. He was very, very helpful."

The research team now includes UM bee specialists, MSU fungal pathologists and insect specialists at Texas Tech University and the Instituto de Ecologia, A.C. in Mexico. Much of the work has been done at Bee Alert Technology Inc. in Missoula, a private company Bromenshenk and his partners started that licenses honeybee technologies discovered at UM.

There still remains work to be done to confirm the pathogens are the cause of CCD. All of that depends on additional testing, which is expensive.

"The definitive steps that we need to complete to prove the cause depends on funding," Bromenshenk said. "We would certainly like to see it completed as soon as possible."

Until then, beekeepers may take care in where they place their bee yards.

The fungal pathogen grows best in cool moist areas. Beekeepers have reported more problems in places with frequent fog or following lots of rain.

Placing bees in warm, sunny locations appears to help prevent outbreaks.

Bromenshenk is looking forward to seeing where this new information takes researchers searching for the source of CCD.

"Even if it's not the cause of CCD, the discovery of the iridescent virus in our North American bees is important," he said. "It warrants additional investigation, as it's a whole different category of viruses than anyone has looked at before. It's a unique discovery."

And a discovery that he looks forward to sharing with members of the Montana Beekeepers Association when they come together in Kalispell next week.

"Since our state has some very large-scale beekeepers, it is a fitting place to unveil this information," he said.

Reporter Perry Backus can be reached at 363-3300 ext. 30, or at


You must be logged in to react.
Click any reaction to login.