Bee Health Decline: Pathogens are the Culprit

July 12, 2013


 University of Montana  researchers studying cause of colony collapse disorder


The bees swarm in the morning heat, their buzz pouring from boxes stacked on Mount Sentinel. Numbering in the thousands, they’re warming up for their morning quest for pollen.


These docile honeybees are players in a national mystery, helping researches at the University of Montana determine what’s killing colonies like theirs across the country. After years of work, the team of sleuths is close to isolating at least one cause of colony collapse disorder and proving it with scientific certainty.


“We still think it’s a pathogen – a concurring infection of at least two different organisms that cause colony collapse, and they all happen to infect the intestines of the bees,” said Colin Henderson, a project research manager at Bee Alert Technology and a professor at Missoula College. “We’ve done whole-colony experiments on this, and it works every time.”


Henderson was called to a national stakeholders meeting in Virginia last October by the U.S. Department of Agriculture. The meeting brought together more than 100 interested parties, from Dow AgroSciences to the Almond Board of California.


During the conference, stakeholders broke into four expert groups to cover pesticides, nutrition, pathogens and genetics. The USDA released its findings in May, summarizing the latest theories and research on colony collapse. The paper outlined steps needed to restore honeybees, along with the $20 billion agricultural industry that relies upon the insects’ pollination services.


Henderson said the issues discussed at the meeting were many, and they may be equally hard to resolve. They range from the practice of transporting bees across vast geographic regions to pollinate various crops, to loss of forage.


Poor nutrition also may be part of the problem, a possible result of today’s agricultural practices, including no-till farming and massive fields of single crops.


“Hybrid corns aren’t bred for seed production, but for grain production, and hybrid corn pollen is pretty sterile,” Henderson said. “In the Midwest, we found bees were going out of their way to avoid corn pollen to find other things, so nutrition is an issue.”


Climate change, urbanization and managed habitats remain suspect as well, as do pesticide use, genetic diversity, handling practices and parasites.


But Henderson, along with lead UM bee researcher and Bee Alert president Jerry Bromenshenk, believes disease remains the primary suspect.


With an eye on the cause, the research team is racing to isolate the culprit – along with technology to alert beekeepers to problems early on, including acoustic tools to measure the frequency spectrum of a hive.


“We’re convinced more of a pathogen – a disease base for CCD,” Henderson said. “We’re doing more experiments now and setting them up. It’s both exciting and frustrating.”


The UM program has worked with the Department of Defense in using bees to detect explosives and land mines. It also has teamed up with the Edgewood Chemical and Biological Center – part of the Army Research, Development and Engineering Command – to find ways of detecting new and previously unknown biological agents.


Along the way, researchers discovered that a particular virus and parasite appeared in nearly every case of colony collapse. They conducted additional lab work and found they could infect bees to create the same phenomenon in a controlled setting.


“We’ve done lab infections with it and it works, and we’ve done captive colony infections in a closed environment, and it works,” Henderson said. “We’re doing three flying colonies this summer.


“If we can take the dead bees and isolate the organisms again, then we’ve identified at least one source of colony collapse. We’ve really come a long ways.”


Standing amid the working bees on Mount Sentinel, Henderson explains Cox’s theorem and how it relates to research. If the progress of their own work were measured on a clock, Henderson believes they’d be in the 11th hour, and they’re very close to proving that a one-two viral-parasitic punch is behind the honeybee decline.


“We got involved with colony collapse disorder when it first broke in 2006,” said Henderson. “That’s taken us down a long road of finding what might be wrong, and we’re still working on that problem.”

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