Hello Neon,

In response to your question about temperature control and varroa mites. I
had a similar question in trying to account for the differences in mite
load between my five hives (range of 17 to 115 mites in a 24 hour Apistan
drop) and a friend's 10 hives in his apiary (2-4 mites in a 24 hour Apistan
drop and confirmed with a 24 hour Coumaphos control). My hives are siting
on a concrete deck and get all the sun that the Puget Sound area has to
offer. My friend's hives (10 miles away) are partly shaded and are on
wooden platforms in grass. We both treat and manage our hives (with queens
from the same source) in almost identical fashion and hence I was trying to
figure out why his mite load was so low. So my thoughts turned to
temperature and humidity differences. Anyone with any other ideas - I'd be
happy to hear of them.

Anyway, in their paper "The Impact of Temperature Gradients in the Brood
Nest of Honeybees on the Reproduction of Varroa jacobsoni" Bernhard Kraus
and Hayo H.W. Velthuis demonstrate that Varroa jacobsoni (I guess this
might not really apply to us in North America with Varroa destructor) has
its reproductive optimum at 33 degrees C whereas the optimum temperature
for brood rearing is 35 deg C. I have not read the full paper to know what
happens to Varroa jacobsoni below 33 or above 35 deg C. Anyone else?

Stephen Augustine
Bees By The Bay