> Is Strauss suggesting that the savannah mite in question became less virulent biologically as a result of some mechanism at work in the bee? Or is Strauss suggesting that in the savanna, natural selection favored less virulent mites? 

My reading is that they are positing bee behavior as the main factor; mite behavior is not implicated in this work. 

They say:

a variety of mechanisms leading to colony survival
and their identification provides us with an array of
traits that can be selectively bred into susceptible
honeybee populations to increase their survival to
infestations by this most damaging parasite.

Nevertheless, a more detailed understanding is
needed in order to identify all the
_possible behaviours of the savannah honeybee_ 
from South Africa (e.g. hygienic and grooming behaviour,
swarming frequency) that may contribute to
keeping mite numbers low and consequently reducing
and/or preventing mite population growth
above the damage threshold for the colony.

             ***********************************************
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