In a message dated 3/11/02 9:26:42 PM GMT Standard Time, [log in to unmask]
writes:


> The theory that I heard was that the Varroa destructor was the Japanese
> haplotype which is less virulent than the Korean haplotype.  This having
> been directly introduced from Japan via Apis mellifera hives taken to South
> America.  When the Africanised bee hit the USA, it came in contact with the
> Korean haplotype and thus its progress was slowed.
>

African/africanised bee point not related to varroa in particular.

One look at a distribution map of scutellata/africanised bees shows that this
slowing and stopping is not a North American phenomenon, no matter how
special they think their case to be. The different haplotypes of varroa
causing it to slow in the US seems to me to be just a coincidence rather than
a crucial fact.

There are limiting latitudes in all ranges where this bee is found, beyond
which, for reasons not yet fully understood, it does not establish a stable
population, and 'die back' takes place over time if introduced.

If the varroa type were the crucial factor the africanised bees would have
progressed much further south in Argentina than they ever have, despite
having had far longer to do it.

Even in their native range you still have the cape bee hanging on right at
the extreme end of the continent, just outside the scutellata limit, and
despite numerous opportunities to do so, they have never come right up Africa
and invaded Europe.

Some latitude linked factors, possibly including seasonality, is at play
causing these bees not to prosper much outside latitude 35 N or S. I dont
pretend to know what it is, but it could serve as a warning to those who
would buy such bees and take them outside this range as to the potential
problems which could be encountered.

And that would open another whole can of worms linked to another thread, and
I dont want to go there again.

Murray