>it takes a large population rearing lots of brood to create the gap
between the brood area and overhead feed resources

I'm finding this quite interesting, and just reviewed the illustration of
the winter cluster on the combs by Farrar.
As far as I observe here in Calif (and see from the observations of
others), the top edge of the heat-generating shell of bees of the cluster
typically rests on honey reserves, with brood below.  It is largely the
honey immediately above the brood that is consumed by the cluster.  And as
honey is consumed, the queen then preferentially lays eggs near the top of
the broodnest, thus causing the cluster to eat its way up into the honey
above.

For a gap to occur between the honey and the brood, large enough to cause
starvation when the cluster suddenly contracts due to a cold snap, it would
mean that the brood at the bottom of the broodnest had not emerged soon
enough  for the cluster to cover both it and some honey above.  That is,
for such a gap to form, it would mean that the cluster had consumed honey
more rapidly above than the brood at the bottom of the broodnest could
emerge.

That would then put a firm number to this phenomenon--since brood emerges
in approx 20 days (perhaps 21 under cold conditions).  So for starvation
due to this sort of gap formation to occur, this phenomenon of rapid honey
consumption above the broodnest would have needed to occur during a 20-day
period.

It strikes me as odd that a colony would expand the broodnest this rapidly
during that 20-day period, during a period when it needed to consume that
much honey.

Comments?


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

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