Aaron,

".....The logic of conducting this experiment in the locations where
V.d. has been
present over a relatively extended period and where acaricide resistance
is
highly pronounced may give a "better" starting point towards tolerant
bees,
but is a bad starting place for maintaining a population of Varroa d.
that
is NOT resistant to chemicals......."

Very interesting mail you composed.

And most makes sense!
BUT, as you suggest, we need to be heading towards IPM techniques to
control the levels of V.d. and cut out the dependence on chemical
applications.
So, why would one wish to maintain populations of V.d.that were or were
not resistant to pesticides such as coumaphos etc.?
Surely we want bees that are resistant to V.d!
Work up those in areas that have had extended exposure to the mites, and
yes support  and select from colonies that indicate better resistance.
The supporting colonies I agree would be better maintained via an IPM
program rather than treating with classic pesticide.
All the better if the mites are not resistant! BUT it is the bees
themselves that are to be selected and progressed with, hence the
primary concern.

I suppose, if I remember correctly, this is a variation on the isolated
experiments taking place under the guidance of Otis Gard in Ontario with
A.m.m. from France!

Have a good weekend
Peter