Steve Davis mentions that bees kept in gums with no frames and had never been
treated for mites were still alive, then he transferred them to regular hives
and treated them, wondering if they might have resistance.
 
Two thoughts come to my mind as I read his message.  One is that yes, it is
possible that they could have some resistance.  The other is that since they
were not raised on foundation or frames and just in the natural comb, they
would most likely have had a lot more drones raised than an ordinary hive.
In that case, since mites reproduce predominantly on drone brood when it is
available, then the drones would have been more affected by the mites than
the workers and the overall hive would have been healthier.  I would think,
though that after the mite population got up to a certain point in density
that the whole hive would be affected.  But the fact that they had never been
treated suggests the possibility of resistance.  The thought that the reason
they were "alive" was that they had a higher population of drones than a
normal hive is intriguing, though.  On the other hand, feral bees would also
have a higher population of drones than a normal hive and they for the most
part have been wiped out by the mites anyway.  The conclusion I must therefore
ultimately come to is that if these hives in the gums had been exposed to
Varroa for several years and survived that it would most likely have to have
been because of a resistance factor of some kind.  That's just where my logic
leads me, unless there are other things of which I am not aware that might
have affected their survival.  I also have a friend that has kept one or two
hives year in a year out and has never treated them and one or the other has
survived, just requeening themselves when they need to.  Are they just
escapees that have not yet been infected with the mites, or do they have
resistance?  I guess the only way to tell is to deliberately infect them and
see what happens to them after that.
 
Layne Westover
College Station, Texas, USA