Thank you Norman for weighing in--didn't know that you were lurking : )

I researched this subject quite a bit, and am in agreement.  Colonies kept
in total darkness and constant temperature in Canadian sheds still resume
broodrearing.  The timing is interesting--in various studies, the least
amount of brood occurs typically in November, and then resumes in early
December, prior to the lengthening of the days.

As far as the influence of photoperiod, the only published research that I
could find was from Al Avitabile.  I questioned him on his findings.  His
unpublished research was unable to make a connection between photoperiod
and the initiation of broodrearing.

Some colonies never cease broodrearing during a cold winter.  Lloyd Harris
in Manitoba had one shed-wintered colony rear brood all winter; it came out
of the shed with a larger adult population than that with which it went in!

Here in the snowy California foothills, I regularly check into hives
throughout the winter in anticipation of almond pollination in February.
Typically, broodrearing (if it indeed shuts down) ceases in mid to late
November, and begins again sometime in December.  It really accelerates
with the first availability of pollen, which comes from alder trees in
early January.

If colonies are stimulated during the winter with sugar syrup feeding, they
will brood up during freezing weather in December.  I also observed the
same in Australia, where there are winter nectar flows from some of the
eucalypts.

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

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