Dave Green wrote, "Someone in the research community needs to be checking
these 'survivors'
to find out why they are surviving, i.e., what is the mechanism of
resistance
to varroa? And is this only a mild-climate phenomenon?"

John Harbo's research suggests there is an inheritable trait in all lines of
bees for suppressing mite reproduction.  Inheritable trait meaning the trait
can be carried across generations (hence a genetic propensity) and he has
observed this across strains of bees.  John speculates that the propensity
to suppress mite reproduction (SMR) is out there in the wild and breeders
can (some do) select for it.

The bad news is he doesn't know what it is about these SMR bees that
suppress the mite's reproduction, he just knows (by empirical data) that if
the bees possess this trait, varroa mites simply do not reproduce
successfully in that population of bees.  Investigation is being directed at
keremones to see if there's something about the "smell" of these bees that
trigger a faulty reproductive response in varroa mites (ED?).  I believe
John's research is pending publication in one of the journals (ABJ or BC)
soon (perhaps this or next month).

It is logical that if this SMR characteristic exists as John's research
suggests, it would become a predominant trait as those populations lacking
this trait succumb to the ravages of varroa.  An interesting question is,
how will the dynamics of adaptation play out in this situation.  Will varroa
also evolve to adjust to the SMR characteristic, or will the predator and
host achieve a happy medium?  Survival of both species suggests the latter.

Aaron Morris - thinking dynamics!