>
> >I assume you are referring to "inbreeding depression" -- the opposite of
> "hybrid vigor."
>

What I was referring to was the artificial selection process practiced by
our queen producers, in which a very limited number of mitotypes (and
presumably) genotypes are selected for.  Nearly none of which (for most
producers) are very resistant to varroa.

>
> >But I believe that honeybees have evolved to a system which combines
> outcrossing and recombination; which is driven away from inbreeding and
> toward hybrid vigor. Which is logical, since heavily inbred colonies die
> and don't reproduce, while hybridized ones tend to thrive and pass their
> evolved traits on.


I don't find strong support for either of those hypotheses.

In the first place, I question whether hybrid vigor is actually common
other than when crossing inbred lines.

As to the second, Kim Fondrik, technician for Dr Rob Page, has worked with
single-drone mated colonies (which produce inbred workers) for many years.
He tells me that many of them exhibit normal vigor and survival.

In nature, hybrids are generally more poorly adapted than either parental
type.  If this weren't the case, then the hybrids would quickly replace the
parent stock, and we would then call the hybrid a parent line.

-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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