> For there to be resistance there must be a genetic trait present in the
> current population that will allow the bee to survive when its beathing
> tubes are clogged with parasites.

It Ain't Necessarily So!  A trait such are good grooming could tip the
balance in bee's favor.  Have a look at the video clip mentioned yesterday
where Dr. Jose' Villa and Dr. Bob Danka videotaped honeybees exhibiting
resistance to tracheal mites.
at:
http://personal.bna.bellsouth.net/bna/b/e/beerich/

Aaron Morris - thinking Porgy and Bess!