To comment on Al Lipscomb:

I rember the Penman-Monteith equation describing the physiology of water
evaporation from plants that I believe can be applied in this case too.
So the water pressure _deficit_, ie the difference in the amount of water vapour
that the air could hold at the surface temperature to the one of the air's
temperature is the driving agent, and not the relative humidity.
The surface temperature here would be the one of the bees, alternatively of the
honeycombs, the air temperature would be the one measured outside the hive in
order to avoid potential condensation problems (as the humidity from inside the
hive has to be transported to the outside).

One _only_ has to find the proper aerodynamic resistance for the latent heat
transfer (ie the drying of the honey) to be computed :-))

As the saturated water pressure depends _about_ exponentially to the air
temperature, the higher the temperature the larger the evaporative deficit,
everthing else equal.
This also means that the _same relative humidity_ will result in higher evaporative
deficit at higher than at lower temperatures, everthing else equal.

"Beyond the flower source issues, bees are evaporating water out of the
nectar to bring it down to the water levels needed for honey. This should be
affected by the _relative humidity_ of the air in their environment. "


Sincerely
Med venlig hilsen


Bernd Kuemmel

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Bernd Kuemmel, stud.lic. (PhD.stud.)
Royal Veterinary and Agricultural University (KVL)
Agrovej 10           +  DK-2630 Taastrup
V: (+45) 35 28 35 33  +  F: (+45) 35 28 21 75
http://www.agsci.kvl.dk/~bek/cfehtml.htm