>
> >The Primorskys survived the better part of a century supporting your
> contention that 'left unmanaged,

generally possesses the ability to rapidly evolve some sort of resistance
> to extirpation by varroa.'


As I recall, the Primorsky beekeepers did use concoctions to control
varroa, although I have no idea as to how effective they were.

>Yet, I'd hardly qualify them as fully adapted.

"Fully adapted" is a loaded term.  Prior to varroa or *Nosema ceranae*,
most races of European honey bees could have been considered as being
"fully adapted" to the insect viruses and *Nosema apis*.  Yet the
evolutionary Red Queen competition between the host and parasite continued
unabated, and occasionally there were epidemics that wiped out large
percentages of the bee population.

 >Having the tools to avoid short term extirpation by varroa only opens the
door to a much longer term natural selection that might result in a more
healthy coexistence

That's exactly the strategy that I use in my own selective breeding
program.  But at a cost.  The rapidity of evolution is dependent upon the
degree of selective pressure.  So you can call it either "longer term
natural selection," or "prolonging the agony."

Let us not forget Dr. Jose Villa's highly informative study of swarm trap
hives in five areas of Louisiana during the invasion and establishment of
varroa (from 1991 to 2006).  This was without the benefit of
Africanization.  His summary:

We conclude that predictable changes in the host parasite
relationship between honey bees and varroa
mites are the most likely explanation
for our observations. Immediately after the arrival of
varroa mites there was a strong impact on colony survival
and reproduction. After a period of 5 to 10 yr, there has
been an improvement and currently colonies seem to be
reproducing and surviving as well as in prevarroa days.
Others have reported similar trends,and it is possible that
this may be a generalized situation in a number of areas.

Changes in Honey Bee (Hymenoptera: Apidae) Colony Swarming and Survival
Pre- and Postarrival of *Varroa destructor* (Mesostigmata: Varroidae) in
Louisiana.  Ann. Entomol. Soc. Am. 101(5): 867Ð871 (2008)

And now I see that Bill brought to our attention:
>It is not Varroa resistance but virus resistance.

As Dr Stephen Martin modeled, a colony need not be especially virus
resistant, so long as the varroa infestation rate did not exceed a certain
threshold.  But Bill's point is well taken--the Russian bees often exhibit
amazing virus resistance, despite carrying high varroa loads.

Of interest, is that the viruses associated with colony collapse vary from
region to region (DWV being nearly universal).

And it's not just viruses.  Once a colony starts to go downhill, any number
of opportunistic parasites can take advantage of the weakened host.  The
parasite that delivers the coup de grâce may be *N. ceranae*, following the
initiation of a virus epidemic by varroa, which then weakens the colony's
resistance to nosema, which then leads to an epidemic of *that* parasite,
resulting in sudden colony depopulation.

Nothing is simple in biology.

-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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