> > I am still convinced as was Brother Adam that resistance to > > tracheal mites can be selected for. > 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 breathing > tubes are clogged with parasites. Hmmm. I think there are many more possible mechanisms. I believe that the mechanism that works best right now is breathing tubes that do not admit the mites. Apparently some bees have hairs or something that restricts the admission of foreign objects? Also, apparently smaller bees have smaller tubes, and some say that the tracheal mite was an external mite until relatively recently when it learned to enter the tubes or found bigger bees that it could enter. allen -- Diary and pictures at http://www.internode.net/HoneyBee/ Cell size, worker bee size, package installation & performance, winter loss, Fondant feeding, Pierco vs. Permadent, unwrapping bees, AFB, varroa, protein patties and more... Over 1000 served to date