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Genetic Condition May Cause Bee Colony Collapse

“It won’t get into bees unless IAPV is integrated into them.”


An Israeli researcher is claiming a possible breakthrough in the hunt for the cause of a mysterious die-off of honeybees in different parts of the world.

A genetic predisposition to an obscure virus may make bees vulnerable to another as-yet-unknown agent which causes colony collapse disorder (CCD), says Ilan Sela of Hebrew University in Jerusalem.

Sela suggests bees with genetic sequences of Israeli Acute Paralysis Virus (IAPV) in their genomes interact with a “biotic entity” which suppresses their immune system and causes widespread deaths in colonies.

“My suspicion is that (CCD) is caused by an opportunistic pathogen and that IAPV lays the background for this opportunistic pathogen to get into the bees,” he said during a recent entomological conference in Winnipeg.

“It won’t get into the bees in that way unless there is IAPV integrated into them.”

Sela, also chief scientist of a research company called Beeologics, hopes to protect against IAPV with a method called genetic silencing, which prevents genetic expression of a bee’s predisposition to the virus.

He stressed, however, that his theory is still preliminary.

IAPV, discovered by Israeli virologists in 2004, has since been suggested as a trigger for CCD, a mysterious syndrome in which worker bees vanish from hives, leaving hives full of honey, larvae and unattended queens but no adults.

First identified in the U. S. in 2006, CCD is now blamed for bee losses in other countries, although not yet Canada, apparently.

Although some research suggests a connection between CCD and new and emerging pathogens such as IAPV, many believe the disorder results from a combination of factors.

“The general feeling among the scientific community right now is that CCD is probably being caused by a wide variety of multiple stresses acting in concert with each other,” Rob Currie, a University of Manitoba entomologist, said during a break in the conference.

“There are certain diseases that are often associated with it. But one individual cause alone is not likely to (result in) the collapse of colonies.”

Other suggested causes of CCD include pesticides, changing weather patterns, inadequate nutrition, environmental stress and the parasitic varroa mite.

The var roa, endemic in North American bee colonies, is believed to suppress bees’ immune systems and leave them open to disease.

But environment alone is not the cause of CCD, said Rheal Lafreniere, Manitoba’s provincial apiarist.

“It may create a condition where CCD can occur because disease can transmit more rapidly or the bee’s health is compromised because its immunity is down,” Lafreniere said.

Although honeybee colonies in the U. S. have been dying at unprecedented numbers and with unique symptoms, not all of it is due to CCD, said Diana Cox-Foster, a University of Pennsylvania entomologist.

She told the conference the U. S. lost 37 per cent of its colonies in 2007, a third of them to CCD. In 2008, colony losses rose to 39 per cent but CCD rates actually declined.

Cox-Foster belongs to a U. S. Department of Agriculture working group trying to unravel the mystery of CCD. [email protected]

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