We have been following the plight of the commercial honey bee and the mysteries of Colony Collapse Disorder (CCD) on this site for some time. Now, according to a recently published study out of Toronto, "Wild bumble bees (Bombus spp.) have also suffered serious declines and circumstantial evidence suggests that pathogen ‘spillover' from commercially reared bumble bees, which are used extensively to pollinate greenhouse crops, is a possible cause." In other words, commercially bred honey bees used to pollinate greenhouse crops may be the catalyst for the overall decline of the North American bee population.
The study was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and Ontario Graduate Scholarships (OGS). By following wild bees living in close proximity to a commercial bumble bee operation in Ontario, the researchers were able to model a slow, and then increasingly virulent, spread of pathogens from the commercial bee population to the wild bees. The closer to the greenhouse, the greater number of wild bees adversely affected. Scientists call this phenomenon of disease transfer from domestic to wild animals, "pathogen spillover".
According to the research:
Most of the parasites in the wild bumblebees were found to be at normal levels except for one intestinal parasite known as Crithidia bombi that is common in commercial bee colonies but typically absent in wild bumblebees. - Yahoo News
Further, the study states that "Bees foraging immediately adjacent to greenhouses also harboured significantly more intense infections, i.e., they carried more pathogen cells in their gut tracts, than bees collected further away." This raises the question of whether the disease is coming from their interaction with the commercial bees, or their proximity to the pesticides and herbicides used in commercial greenhouse growing. The scientists in this study believe that it is definitively the interaction with the commercial bees, stating "the mechanism of pathogen spillover is clear: infected commercial bees frequently escape from greenhouses and share nearby flowers with wild Bombus, thereby providing sufficient opportunities for the transmission of disease."
Unfortunately, this particular parasite is often lethal to bees. While the study still does not identify the cause of the pathogens that have led to colony collapse disorder and are now decimating wild bee populations, it may bring scientists a bit closer to understanding and solving the issue. In the meantime, the research seems to support what many have believed for a long time; that recently released commercial pesticides and herbicides, along with chemical fertilizers, have weakened the immune systems of commercial bees and are the main culprit in CCD. And the wild bees that interact with them are paying the price, too.
- The Potential Impact of Colony Collapse Disorder: An Excerpt from "A Spring Without Bees"
- Disappearing Bees - Colony Collapse Disorder Affecting Honeybees
- Pollution, Pesticides and GM Crops Killing Bees?
- The Bats and the Bees
- 60 Minutes on Disappearing Bees
- The Vanishing of the Bees
- Bee Die-offs from Multiple Causes
- Organic Bees Surviving Colony Collapse Disorder (CCD)