Tuesday 23rd of May 2017

OnEarth magazine


The Latest Buzz on Bees
By Eric Scigliano
February 22, 2012
A beekeeper's discovery could help save our honeybees from a massive die-off
About five years ago, researchers studying colony collapse disorder, the syndrome in which most of the honeybees in a colony die or disappear without warning, discovered a new potential culprit: a fungal pathogen called Nosema ceranae. While they didn't believe it was the sole cause of colony collapse disorder, or CCD, evidence suggested that it played a part in this epidemic, which has had severe effects on American agriculture. (Honeybee pollination is responsible for a third of the food we eat; crops that rely on it are valued at $15 billion annually.)
As scientists debated Nosema ceranae's role in the CCD mystery, Dan Harvey, a Washington State beekeeper, gloomily absorbed reports that his wet corner of the Pacific Northwest was likely a perfect incubator for the ravaging fungus. After many years of breeding disease-free bees, Harvey saw at least 90 percent of his stock disappear in the winter of 2007-2008. The same percentage died the following year. That devastating one-two punch threatened to destroy his entire livelihood.
But Harvey wasn't about to give up. For years he'd crossbred his commercial stock with hardy local feral bees -- the descendants of hives cultivated by early-twentieth-century homesteaders -- that had survived in the harsh environment of the Olympic Peninsula rainforest. This crossbreeding had yielded a stock that was resistant to the common but deadly varroa mite, a parasite that has also been implicated in CCD. Harvey wondered if there might exist, somewhere in his neck of the woods, wild bees that had developed a resistance or tolerance to Nosema ceranae.
For the better part of two years Harvey tramped through the forest, "just catching bees off flowers," and, with the help of scientists at Washington State University and the U.S. Department of Agriculture, testing them for the fungus. And then one day, in a patch of young forest not far from his hometown of Port Angeles, Harvey found something remarkable: a feral colony that had somehow managed to remain entirely Nosema ceranae-free.
"I called them the bear bees, because a huge bear knocked the bait hive over," he says. But these bees had withstood far worse threats than bear attacks. "Nosema ceranae was everywhere, except this one wild swarm. I knew they had to be survivor stock."
Harvey brought some bees back to his beeyard, where he and his wife, Judy, crossbred them with stock from other colonies -- including one whose queen, he notes, will eject any varroa-infested brood from her hive. Now USDA researchers are testing the results of Harvey's crossbreeding techniques, trying to determine how well, not to mention why, these bees are handling pathogens that have destroyed other colonies. "Dan Harvey is the only person I've heard of who thinks he might have bees with resistance to Nosema ceranae," says Bob Danka, a USDA research entomologist. "He probably has the clearest sense of variance and susceptibility of anyone around."

Meanwhile, Dan Harvey continues to raise his crossbred bees without using chemical miticides and pesticides, which he believes can act as stressors and hamper the process of natural selection. His hives, once decimated, seem to be on the rebound. The result of this citizen-scientist's efforts might just be a honeybee that can stand up to two of the greatest scourges known to apian science -- and conceivably even a honeybee that could help researchers unlock the mystery of CCD, and send it buzzing into the past. Pretty sweet.
Fast Facts
100: Percentage of U.S. apple, broccoli, and carrot crops dependent on pollination
90: Percentage of pollinators for these crops that are honeybees
50: Percentage by which U.S. managed-bee population has declined since 1940