March 7, 2011

Cause Of Honeybee Colony Collapse Sought By Researchers

Scientists are seeking a way to identify and eliminate mass deaths of the honeybee, the primary pollinator for the world's plants.

The die-offs affect more than 30 percent of bee colonies in the United States and more than 20 percent in some European countries.

A few possible causes identified in Colony Collapse Disorder (CCD) include blood-feeding parasites, bee viruses, fungi, pesticide exposure and decreased plant diversity causing poor nutrition for honeybees, experts tell Reuters.

It is not just honey lovers that are affected, but a large portion of the global agricultural market as well. Fifty-two of the world's 112 leading crops rely on pollination, apples, soybeans, cocoa and almonds being some of the largest examples. One study by economists, in 2009, put the value of insect pollination, mainly by bees, at about $212 billion.

Observers worry that a decline in the number and health of bees will deepen a global crisis unfolding from limited crops and soaring food prices especially with human population increasing as it is. Showing up as an emerging international threat, England has lost more than half its hives in the last two decades, and bee losses are increasing in Asia, South America and the Middle East.

Some scientists point to commercial agricultural pesticides such as clothianidin, as a possible cause.  Clothianidin has been linked to millions of bee deaths near farming areas in different countries. Banned in some European countries, it remains EPA-approved and is used on US regularly on crops such as corn, wheat and soy.

Parasites - such as the varroa destructor, which clings to a bee as it feeds on hemolymph, or bee's "blood" - spread viruses to the insect. Major infestations will typically wipe out beehives, explains Keith Delaplane, entomology professor at the University of Georgia.

A US-Israeli biotech named Beeologics now makes an antiviral medicine to fight the infections that exploit a native immune mechanism and also boosts a bees' tolerance for disease, claim multiple researchers involved with the studies.

Another possible cause for the die-offs is a combination of a virus and a fungus, which was found in all collapsed colonies in a US study last year. The combination of the viral-fungal duo may destroy bee memory or navigation functions contributing to the collapse of the colony.

Independent honey producers are seeing less damage than commercial apiaries, says small producer Dan Conlon. With his 700 hives at Warm Colors Apiary in South Deerfield, Massachusetts, Conlon's bees tend to be resilient, living in a rural, diverse habitat. "Most of those reporting heavy losses run large operations and are focused on migratory pollination for their income," Conlon tells Reuters.

"Early bee reports are poor throughout the United States this winter, including Georgia, which appears to be losing about one-third of its colonies," Delaplane concluded.

As of last summer, there were 2.8 million managed US hives, the USDA claims. That's only about half of the nation's 5 million hives tallied back in the 1940s. The nation produced 176 million pounds of honey last year, with wholesale prices reaching a record $1.603 per pound, according to the USDA.