"We have to understand first how many elements can be brought to bear on a
controversy; once this is understood, the other problems will be easier to
solve." Bruno Latour 1987
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I have followed the cell size / bee size discussion with great interest
but have not had time to provide a comment before now. (This is fresh fig
selling season for me at the local Farmers' Market, an activity that takes
almost all free time.)
The somewhat general discussion we had at first eventually evolved
mostly into a very narrow debate on cell size ("Angels on the Head of a
Pin" --- in Allen Dick's words --- not original with him, of course).
Another analogy: Debating the size of leaves on a tree when we have to
consider the forest as a whole.
At the onset I should mention that I have talked with the Lusbys and
have seen the results of their cell size experiment; their gains are real.
However, let us step back for a moment and view the forest. The outline
below (without comment) should place much of the problem in perspective.
THOUGHTS ON VARROA What we know - What we can do
I. The Animals
A. The bees (various races, change after varroa arrival?)
B. The mites (Varroa destructor: Japanese & Korean strains)
1. Development of resistance to toxins
2. Rapid generation time
II. One Approach: Change the Bee
A. Selective breeding
1. Resistance
2. Tolerance
B. Let Nature take its course - Accommodation
III. Other Approaches: Kill or Hamper the Mite
A. Toxins
1. Apistan
2. Cuomophos
3. Formic acid
B. Benign (?) chemicals
1. Mineral oil
2. Essential oils
C. Physical manipulation
1. Drone brood removal
2. Open bottoms on hives
3. Smaller cell size
IV. Other Factors
A. Length of season
B. Intensity / duration of nectar flow(s)
C. Beekeeping practices (e.g., dividing, feeding)
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MY COMMENTS
Peter Borst already provided a good summary and assessment of current
information about cell size and varro; I will not unnecessarily repeat that
information.
Bob Harrison wrote: "Researchers look for complex answers first.
Beekeepers look for simple answers first." I would rather say that a good
researcher recognizes and tries to deal with complexity without becoming
too committed to an initial hunch. A good auto mechanic does the same. We
call this the Multiple Inference Approach. One can find a description of
that approach in item #22 on
http://www.beesource.com/pov/wenner/index.htm).
Unfortunately, most research seems conducted in a linear approach ---
alter one factor and hope a "simple answer" emerges. These past few years
on BEE-L we have seen several such examples. I believe one of Allen Dick's
main objections to some of the input on the network has been that altering
only one factor and achieving success does not establish that that
particular factor was responsible; something else might have changed at the
same time, unbeknownst to the researcher (here I include beekeepers who do
research).
Now let me comment on a few specific points of the above table, as
referred to by the assigned numbers (not in the same order). In so doing,
I will try not to repeat too many comments by others.
III. Kill or Hamper the Mite
Any toxin is only a short term "solution," since the mites have such a
rapid generation time; some mites always survive treatment and become a
stronger strain. Worse yet, one then has no selection for bees resistant
to or tolerant of mites but instead keeps alive a weak strain of bees.
If mineral oil had worked as originally claimed, we can be sure that
hundreds of beekeepers would be using that technique by now.
Experimentation with essential oils seems also to follow the linear
approach; time may tell whether it has promise.
In our work on Santa Cruz Island, we learned that colonies had no ill
effects from a varroa introduction until a full two years after
inoculation. Even then, many colonies survived an additional two years (a
few still survive, seven years later). That means one would have to run
any experiment for more than four years to determine whether a given
treatment worked. Mike Allsop outlined a protocol for such
experimentation.
I. The Animals
We have now had varroa mites in the U.S. for about 15 years. Whereas
bees in managed colonies have likely changed little (due to the use of
toxins to control mites), feral bees in areas remote from managed colonies
may have changed a lot --- since we now find thriving feral colonies in
such areas (as covered in my September 1999 AMERICAN BEE JOURNAL letter).
(Some of the feral colonies we have extracted from buildings and trees have
now thrived for four years without treatment of any kind.)
Whereas those feral bees may have become resistant or tolerant, the
mites also may have changed significantly in all that time. We have both
Japanese and Korean strains in California; the more virulent strain may
have become largely phased out by natural selection. Bill Truesdell used
the word "accommodation"; that word serves well, until we can determine
whether the bee or the mite has changed (or both).
II. Change the Bee
Selective breeding for resistance or tolerance (e.g., "hygienic") is
indeed possible but requires an enormous amount of effort and expense.
That approach also relies on the validity of perhaps several assumptions.
Furthermore, since queens mate in mid-air (often with drones from feral
colonies), beekeepers cannot readily maintain a resistant or tolerant
strain of bees if one is found.
John Edwards wrote: "All that is required is a population of animals
(bees), a pressure (varroa), and the observational skills and time to
select for survivors." I believe that is what has happened to the feral
colonies in our extensive backcountry. Nature has taken its course; those
bees and mites have apparently reached some sort of accommodation.
IV. Other Factors
Allen Dick has raised this issue quite well. Any experiment conducted
by use of a linear approach that achieves apparent success may well be a
consequence of some other factor(s) that changed at the same time.
Adrian
Adrian M. Wenner (805) 963-8508 (home phone)
967 Garcia Road (805) 893-8062 (UCSB FAX)
Santa Barbara, CA 93106 [http://www.beesource.com/pov/wenner/index.htm]
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* "The hardest thing to understand is why we can understand
* anything at all."
* Albert Einstein
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