Interesting discussion on wintering bees!

   But I think that much of the discussion fails to consider the
difference in bee physiology from our own.  I don't think that
insolation has an important effect when above flight temperature or
when it is  below dormancy temperatures.   The importance of the wrap
is at that marginal temperature zone and fluctuations around it. A
colony of bees at a temperature below which it is forming a tight
cluster is very efficient at conserving energy.

  A constant cold temperature is just the ticket for an easy winter.
When temperatures are jumping up & down, allowing (forcing) the cluster
to break/reform/break/etc this is very stressful and makes for a
difficult winter for several reasons.  The bees tend to consume more
food and they release more moisture.  A constant even temperature with
periodic breaks that allow for the hive to cleanse & refuel is ideal.
The idea of a vernalization chamber is to keep the bees dormant through
the duration thereby reducing their activity--their metabolism.
Remember insects are temperature dependent and slow down as the
temperature cools.   A cluster of bees needs to keep the queen warm but
the outer cluster temperature is almost ambient (or just above
freezing).

My view--& this is my two cents--is that the real benefit of the wrap
is in allowing the cluster longer periods of activity as the
temperatures fluctuate back and forth across that critical zone
--usually in the early spring & late fall. This allows for more
activity just prior too  and after the period of inactivity allowing in
effect for a shorter overall winter.  Knowing this one can feed right
after the honey is pulled to keep an artificial flow going & hopefully
brood rearing as well as make sure the hive is crammed full.  Then in
the spring the feed comes back on again stimulating brood rearing &
colony growth.   Wrapped hives get a jump on early development & growth
as they are able to maintain hive temperature when the cluster is
active not when its dormant.  The insolation allows greater periods of
activity only when the temperatures are moderate--not extreme because
the colony will cluster going into conservation mode.

There is a trade off here.   A wrapped hive that has broken cluster
early & stays active longer will need more stores to maintain this
level of activity.  It will probably need fall & spring feed with
extender patties (spring) too boot.   The advantage is that one will
have early bees for an early flow or many early bees for more or larger
splits.

By mid summer wrapped or unwrapped bee colonies will have equalized!

Mike

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