Maybe I was napping through the meetings when SMR was being discussed, but I
got to wondering about drones, so I wrote John Harbo to ask.  His reply has
bearing on understanding varroa dynamics, and I offer it here with his
permission, and his disclaimer.

My question:
> > In colonies headed by SMR queens, and after a generation has been
> > raised, are the mites equally non-reproductive on drone brood as
> > on worker brood?
> >
> > Or does the presence of drone brood lower the tolerance to mites
> > substantially?
> >
> > What I am wondering is whether an SMR colony which is raising drones
> > in abundance has the same degree of protection, by SMR, as one which
> > is raising worker brood principally, and very few drones.

His reply:
> Mites do reproduce in SMR drones. Most of our data was in colonies
> with free-mated SMR queens where the drones were pure SMR and the
> workers were not. The presence of drones often sparked an increase in
> mite reproduction in worker brood too (My guess is that mites that are
> produced in the drone brood of SMR colonies are reproductive when they
> enter their next cell, while those produced in worker brood are
> nonreproductive as long as the next cell that they enter is a worker
> cell). So yes, overall resistance to varroa declined when drone brood
> was present.
>
> I think we found less reproduction in SMR drones than in control
> drones but the bottom line was that the SMR trait did not save the
> drones except by reducing the mite population in the colony when
> drone brood was not present in significant amounts. Our data is
> pretty weak on this subject, and we hope to address this issue in
> more detail, hopefully next spring.

> > Very interesting.  Do you mind if I quote this in discussions?

> I don't mind as long as you make it very clear that this is just my
> opinion  and that my opinion is  based on only 10 or 15 scattered
> observations. Usually in situations like this, I am not exactly correct,
> so I expect to be surprised when we get more data.

I thought this may answer (and raise) some questions, even in dealing with
non-SMR hives, and particularly in regard to understanding the model at
http://www.csl.gov.uk/science/organ/environ/bee/varroamodel/, or the
calculator at
http://www.csl.gov.uk/science/organ/environ/bee/varroamodel/app.cfm.

At "The New Varroa Model" page, pay particular attention to the chart titled
"Comparison of the number of mites emerging from drone brood and worker
brood as predicted by the model - emphasising the importance of drone
brood".

allen

Is this list called BEE-L or VARROA-L?
http://www.honeybeeworld.com/diary/

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