In a message dated 14/11/05 13:35:02 GMT Standard Time, [log in to unmask]
writes:
<<In both these passages there is reference to time. In the case of the
moths,
it is decades, not eons. But moths are *highly adaptable*, and you can find
numerous examples of camouflage and mimicing. What I am saying is that the
facts do not support the emergence of a wild population of european honey
bees in the US that is resistant to varroa in such a short time. Bear in
mind, too, that the varroa are evolving and a less virulent type may arise
that *does not kill its host*.
I. G.>>
But then we have the example of UK bees, which developed resistance to
tracheal mite in a relatively short time. From what I can gather, the small boxes
traditionally used by UK beekeepers created a situation where badly infected
colonies didn't survive, since they were more active in winter, used more
stores, and starved as they ran out. This created major selection pressure, and
the result is that TM is no longer a problem here.
I think the assumption that evolution will always take a long time is a
dodgy one. Two things are needed; firstly, a new gene has to develop, and
spread through the population, at least at a low level. This may well take a
long time. Secondly, selection pressure or genetic drift need to bring that gene
to a dominant level within the population. This can happen quite quickly.
Regards,
Robert Brenchley
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