> Another important note: as far as I'm aware, the only place on Earth that
honey bees have gone extinct due to varroa is on Santa Cruz Island (which
hosted an inbred population of only about 60 colonies).  Thus, the
preponderance of evidence is that if humans don't meddle, bees are able to
fairly rapidly evolve resistance to varroa.

This is an example of misapplication of terminology. The loss of a species in an isolated location is not extinction. Extinction refers to "a species, family, or other larger group having no living members." 

> In the case of varroa, one should read Allsopp's analysis of what happened
in two different races of A. mellifera (scutellata and capensis) when
varroa invaded South Africa.  The African races again serendipitously
possessed traits for resistance (as do our European stocks). 

You raise an important point: the African bees already "possessed traits for resistance" -- probably heightened olfactory sensitivity, aggressive hygienic behavior, and absconding to evade predators (including brood infestations).

> The point is that those ferals (of many different matrilines) did not
disappear.  They survived varroa and everything else.  And they appear to
be slowly rebounding, despite the continual immigration of varroa from
nearby managed hives.  

I am not sure this is supported by the genomic work. The mDNA is useful for tracking matrilines but not much else. The populations may be surviving "despite" the presence of managed hives, or because of it. Zayed and Harpur analyzed genetic diversity and pointed out that diversity is strong in US populations as a *result* of influx of genes, including African genes. A *simple explanation* is that wherever African genes have been incorporated (Arizona, Texas, California, etc) varroa is far less of a problem. 

Further, there are environmental factors. Isolated colonies seem to fare better than colonies in apiaries, especially large ones. And honey bees kept in southern states have a more moderate growth curve than in the far north where the colonies have a population peak in July, which subsequently tends to drop drastically in the fall. The rapid increase seems to correlate with a rapid increase of varroa.  

> So despite our worst efforts, evolution appears to be ignoring us, and ticking along quite nicely.

Separating evolution from human directed selection is very difficult, if not impossible. Some would say humankind is constrained by evolution; others would suggest that we are now the dominant force, that wild nature's fate rests in our hands. Thoreau's statement that "in wildness is the preservation of the earth" was repurposed to "in civilization is the preservation of wildness." -- Kaufman, W. (1994). No turning back: Dismantling the fantasies of environmental thinking. 

P

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