Experts have speculated and supported opposing notions on whether natural or artificial selection "works" in honey bees.   The lab out of which the quoted paper comes from has argued for a long time that naturally selected material is the only viable venue.   One can quibble about the strength of conclusions, but there are fairly solid examples of both natural and artificial selection working when it comes to many traits, including resistance to varroa.  And one can speculate endlessly on whether inbreeding and loss of diversity can obliterate the benefits of any selection, because there are likely examples of costs, depending on the trait and the bee population it is in.

I am not sure there is a lot of evidence that a selected trait that works somewhere fails somewhere else.   Traits that are fairly fixed and highly heritable are robust enough to lack much of what geneticists fear most: genotype by environment interaction.  What does happen routinely is that selected material when tested in fairly controlled environments can perform superbly for a given trait.  For example, close to three decades ago Roger Hoopingarner and John Harbo, using single drone inseminated queens, stumbled upon a few colonies that in controlled field tests had the holy grail: negative mite growth.  After many years of research and scrutiny, honey bee colonies with the right dose of selective varroa removal behavior can keep mite levels "below threshold" and be good at all other things commercial beekeepers expect.  One experiment, in which colonies with high VSH and low VSH were started from a giant mixed package with a known amount of mites produced what we referred to as the duck head experiment, the outline created by the infestation levels.  The neck was the common starting infestation level.  Susceptible stock increased mite levels to the top of the head, resistant went lower.  At that point, queens were exchanged between colonies, and formerly susceptible colonies dropped their mite levels, formerly resistant increased, with the values crossing and plotting the open duck bill.

What is common, not just with VSH material, but pretty much any other selected characteristic, is that once it gets put out to the wolves of hobby beekeeping and commercial operations things get extremely murky.  The presence of original queens is doubtful.  The matings with drones of equal "value" does not happen.  The disease and environmental challenges to colonies are all over the place in the real world.  And queen producers advertise qualities that are not as fixed as one would want.  Pet peeve: judging the merits of any genetically improved stock from the above dynamics, and saying that selection does not work is a superficial misreading of the situation.

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