- Author: Kathy Keatley Garvey
Entomologists, geneticists and virologists are still searching for the cause of colony collapse disorder (CCD).
Yes, they're still searching, and no, there' s no known cause yet.
CCD is a mysterious phenomonen characterized by adult bees abandoning the hive. They leave behind the brood and stored food.
When we attended the 55th annual meeting of the Entomological Society of America in December 2007, one of the highly attended seminars dealt with the plight of the honey bees. Pennsylvania State University entomologist Dennis vanEngelsdorp and USDA entomologist Jeff Pettis were among those addressing the crowd.
In research just published in PLOS One, a peer-reviewed science publication, they and their colleagues found that a higher total load of pathogens--viruses, bacteria and fungi--appears to show the strongest link yet with CCD.
The researchers examined 91 colonies from 13 apiaries in Florida and California. They screened for bacteria, mites, Nosema (protozoan parasites) numerous viruses, nutrition status and 171 pesticides. They also sampled adult bees, wax comb bee bread (stored and processed pollen) and brood.
"Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCDm" they wrote. "Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies."
Their research, the first comprehensive survey of CCD-affected bee populations, suggests that CCD "involves an interaction between pathogens and other stress factors," they wrote. They presented evidence that CCD is "is contagious or the result of exposure to a common risk factor."
Bottom line: High pathogen loads are linked to CCD symptoms, but scientists still don't know what causes bees to become infected with SO MANY pathogens.
What this research does is narrow the direction of future CCD research. It's a big step in the right direction.
"Help the bees" continues to be a resounding cry. Helping to fund the research is Häagen-Dazs (about 50 percent of their ice cream flavors depend on bee pollination). Those visiting their educational Web site can donate funds to Penn State and UC Davis.