With our cooler weather and shortening days, some of our local flora are producing food for the bees, allowing them to produce critical brood prior to winter. The bees are taking advantage of the favorable weather to forage.
Unfortunately, something else is also occurring—the drifting of mites from highly-infested hives into some of your hives. I’m in the middle of a detailed and expensive, but fascinating field experiment to learn more about that mite drift. Thanks to Brion and Alice Dunbar, Sandy Honigsberg, Anna Mudd, and Brooke Molina for helping to glue some 6000 painted steel discs to the backs of bees in colonies that I’m intentionally allowing to collapse from varroa/DWV. Briefly, we’re using magnetic entrance capture traps to recover the tags, as well as using stickyboards to quantify the amount of mite immigration into surrounding hives.
The experiment is about half completed at this time. So far, our findings are of considerable interest.
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We’ve confirmed that some hives in the same yard tend to suffer from far more mite immigration than others
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A number of bees have drifted to hives in yards a half- and a full mile distant
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So far, it appears that there may be relatively more drift to distant hives than to hives that are nearby
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A hive at this time of year can pick up ~10 mites per day, day after day, from other hives
The above findings may help to explain the late-season spike in mite counts that many of us observe in our hives. We’re collecting a ton of data, and hope to shed light on exactly how this happens.
That said, our Ag Commissioner, Chris de Nijs and ranch owner Laura Barhydt are working with me to create a bee ordinance for Nevada County to prevent the overstocking of hives in the County. Our fear is that a single irresponsible commercial beekeeper, by placing a thousand hives with syrup cans next to either Grass Valley or Nevada City, could easily ruin any chance of any local beekeeper making a honey crop. That would be a perfect example of Dr. Garrett Hardin’s “The Tragedy of the Commons” (http://science.sciencemag.org/content/sci/162/3859/1243.full.pdf).
I want to thank those beekeepers who attended the Ag Advisory Commission meeting in September—their attendance and support of the measure made a big impression! We will want an even greater show of support when we present the final version to the Board of Supervisors later this year (we hope to get the ordinance in place by spring). I will send out a copy of the proposed ordinance to all members in advance, and the time and place of the meeting. Since we’d like to have unanimous support for the ordinance, we solicit comments during the drafting process.
Hive management tips: ideally, your colonies at this time will be nearly free of mites, with plenty of healthy sealed brood, and heavy with honey for the winter. They should be out of cold or damp air pockets, and if possible be exposed to morning sun.
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com
