>
> >What do we think about the relation of Varroa and Hive internal humidity?


A widely-cited study by Kraus &  Velthuis  (Naturwissenschaften 84, 217–218
(1997)) concluded that:
" V. jacobsoni females obviously react very sensitively to high RH and
almost never reproduce at levels above 80% RH "

I strongly question the above, since RH within a capped cell is likely much
higher.  Additionally,it would mean that mites would be unable to
reproduce in the Southeast any time that ambient temperature was at or
above 95F and RH at or above 80%, since there would be no physical way
for the bees to then reduce the humidity below 80% in the broodnest.

Surprisingly, despite this paper being widely cited, I can find that anyone
has attempted to replicate the experiment.  And varroa appears to be able
to readily reproduce in the Southeastern states during hot, humid weather.


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

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