Subject: | |
From: | |
Reply To: | |
Date: | Sat, 20 Jun 2020 09:45:05 -0700 |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
Yes, the paper was a review. Of concern is that many of the firm "facts"
were supported by single citations, meaning that no one else has replicated
those studies to confirm. This, alas, is a widespread problem with bee
research, especially of that performed in the last few decades.
> have never been satisfied with any explanation of how varroa spreads so
rapidly in the landscape. Surely "robbing" can account for it somewhat
Robbing yes in areas in which colony collapse from varroa/DWV occurs where
there is still a nectar flow occurring. But robbing at collapse does not
typically occur in Mediterranean climates.
What I found in my field experiment with tagged bees (yet unpublished) is
that there is continual drift of bees between colonies up to a mile
distant. In my experiment, there was far more drift to colonies 500 ft to
a half mile away than would be expected. Mite immigration (measured by
actual count) can be considerable without any associated robbing.
>the chief pitfall is that whatever honey bee stock appears to be varroa
resistant, or varroa tolerant, is generally identified in a breeding
program which uses small to medium sized colonies.
There is a huge difference between "tolerance" (in which parasite
reproduction is not controlled by the host) and "resistance" (in which
parasite buildup is prevented by the host).
Large colonies develop much larger varroa populations simply by virtue of
producing far more brood, and by later exhibiting a greater proportional
reduction in worker population (my own published findings).
Any breeding program that uses isolated or small colonies is of little
practical value.
In my own selective breeding program, the most mite-resistant colonies are
often the largest in most productive in the apiary (we run about 55
separate apiaries).
And any colonies considered for selection should be exposed to "normal"
mite immigration via bee drift. In my own program, I intentionally exposed
a number of breeder colonies to collapsing colonies in the same yard.
Although mite counts spiked a bit during the collapses, the resistant
breeder colonies were able to bring counts back down (sometimes to zero)
without intervention.
I'll be writing an update about our progress soon. Still too early to
claim that all of our stock is mite-resistant, but last season we were at
around 10% by fall, and 7% by the next spring. Progress is slow, but
encouraging. And I've now learned how to improve my selection process.
--
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|
|
|