The cause of Colony Collapse Disorder still remains a mystery
A recent survey found that about 35% of all the colonies in the U.S. died last winter. Of those that died, 71% died of natural causes, 29% from symptoms that are suspected of being colony collapse disorder. Doing the math that comes to at least 10% of all the bees in the U.S. last year died of Colony Collapse Disorder.
In October 2006 Dave Hackenberg, a professional migratory beekeeper, dropped off 400 colonies of bees from Pennsylvania to spend the winter in the warmth of central Florida. When he returned to his Florida apiary a month later he was surprised to find that many of his bees were missing. The number of bees in hives that were still inhabited had dropped greatly, these hives contained only the queen and some younger bees, though the colonies still had stored nectar, pollen, and many developing bees. The older foraging bees, who specialize on gathering nectar and pollen to feed the hive, had simply disappeared. Stranger yet, the wax- and honey-eating pests that usually infest empty honeycombs, wax moths and small hive beetles, were absent from the collapsed colonies. In the end only 9 of the original 400 colonies survived.
Recent Survey
The information provided here was generated by a survey conducted by the Apiary Inspectors of America. They took the survey in January and February this year, and in the process, gathered information from 18% of the colonies in the U.S.
The survey found that about 35% of all the colonies in the U.S. died last winter. Of those that died, 71% died of natural causes, 29% from symptoms that are suspected of being colony collapse disorder. Doing the math that comes to at least 10% of all the bees in the U.S. last year died of Colony Collapse Disorder. I believe that is a significant number of colonies.
Unfortunately, the survey had to be conducted early on to get numbers to congress and the surveyors weren’t able to count the bees still under snow banks in the north. Now that the snow has mostly melted, the losses there have been found to be staggering, but it’s not known yet what proportion, if any, died of CCD. In any event, the losses now are estimated, by my survey this week anyway, to be, instead of 35%, closer to 44% of all the U.S. bees died last winter. Again, doing the math, that comes to 1.1 million colonies, just shy of what’s needed for almond pollination next spring. Hmmmm….
This survey, conducted by the Apiary Inspectors of America (AIA) in collaboration with the USDA-ARS Beltsville Bee Lab was done to not only count dead beehives, but to help determine the distribution of various bee parasites and pathogens. Preliminary results from this survey reveal:
- Nosema (a gastrointestinal disease) levels tended to be higher in colonies collected from CCD-suspect apiaries
- Average varroa mite-infestation levels over all sampled colonies were approaching critical levels (9.5 mites/100 bees), but levels did not differ between colonies in CCD-suspect and non-CCD suspect apiaries.
- Israeli Acute Paralysis Virus (IAPV) was found in 9 of the 11 states sampled, and in 47% of all sampled colonies.The last of these finding begs the question, “What should beekeepers do who are or suspect their colonies are infected with IAPV?” To answer this question a review of both published and the most current data from multiple research efforts is in order.
