"Just as it is tempting to take natural selection to extremes, it is tempting to look for the evolutionary advantage of any trait of an organism — in other words, to see adaptations<http://evolution.berkeley.edu/evolibrary/glossary/glossary_popup.php?word=adaptation> everywhere. Of course, the natural world is full of adaptations — but it is also full of traits that are not adaptations, and recognizing this is important. " taken from defining adaptation: http://evolution.berkeley.edu/evolibrary/article/misconcep_06 most probably apis mellifera had been challenged before with tracheal mite, chalkbrood, and AFB, therefore the code was there. It just have show up. I do not think the same applies to varroa. We shall see if the base code is able to cope, adapt or mutate. *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html