Military joins fight to find bee killers

DENVER — It has been one of the great murder mysteries of horticulture: What is killing the honeybees?

Since 2006, 20 percent to 40 percent of U.S. bee colonies have suffered "colony collapse," with each colony containing about 50,000 insects. Suspected culprits ranged from pesticides to genetically modified food.

An unusual partnership — of military scientists and entomologists — appears to have achieved a major breakthrough: identifying a new suspect, or two.

A fungus tag-teaming with a virus apparently interacted to cause the problem, according to a report by Army scientists in Maryland and bee experts in Montana in the online science journal PLoS One.

How that double-whammy kills bees remains uncertain, the scientists said; a subject for the next round of research. But there are clues: The virus and the fungus proliferate in cool, damp weather, and both do their dirty work in the bee gut, suggesting insect nutrition is compromised.

"It's like chasing a ghost; you never know where it's going to turn up next," said Dr. Jerry Bromenshenk, a scientist at the University of Montana in Missoula.

One perverse twist of colony collapse that has compounded the difficulty of solving it is that the bees do not just die; they fly off in every direction from the hive and then die alone and dispersed. That makes large numbers of bee necropsies problematic.

Bromenshenk's team at the University of Montana and Montana State University in Bozeman and scientists at the Army's Edgewood Chemical Biological Center northeast of Baltimore said in their jointly written paper that the virus-fungus one-two punch was found in every killed colony the group studied. Neither agent alone seems able to devastate; together, the research suggests, they are 100 percent fatal.

"It's chicken and egg in a sense; we don't know which came first," Bromenshenk said of the virus-fungus combination, nor is it clear, he added, whether one malady weakens the bees enough to be finished off by the second, or whether they compound the other's destructive power.

"They're cofactors, that's all we can say at the moment," he said.

Research several years ago at the University of California, San Francisco, had identified the fungus as part of the problem. Several RNA-based viruses also had been detected. But the Army/Montana team, using a new software system developed by the military for analyzing proteins, uncovered a new DNA-based virus and established a linkage to the fungus, N. ceranae.

"Our mission is to have detection capability to protect the people in the field from anything biological," said Charles Wick, a microbiologist at Edgewood.

Bees, Wick said, proved to be a perfect opportunity to see what the Army's analytic software tool could do.

"We brought it to bear on this bee question, which is how we field-tested it," he said.

The Army software system is designed to test and identify biological agents in circumstances where commanders might have no idea what sort of threat they face. The system searches out the unique proteins in a sample and then identifies a virus — or other microscopic life form, such as bacteria — based on the proteins it is known to contain. The power of that idea in military or bee defense is immense, researchers say, in that it allows them to use what they already know to find something they did not even know they were looking for.

It took a family connection — through David Wick, Charles' brother — to connect the dots. When colony collapse became news a few years ago, David Wick, a tech entrepreneur who moved to Montana in the 1990s, saw a television interview with Bromenshenk about bees.

Wick knew of his brother's work in Maryland and remembered meeting Bromenshenk at a business conference. A retained business card and a telephone call put the Army and the Bee Alert team together.

Scientists in the project emphasize that their conclusions are not the final word. The pattern, they say, seems clear, but more research is needed to determine, for example, how further outbreaks might be prevented, and how much environmental factors such as heat, cold or drought might play a role.