>
>I have often read the comments that cold weather does not kill bees.
>Other factors related to wintering such as lack of adequate feed, mites,
>queen status and disease are the real killers.  I have never been too
>sure of this, but I think I am now a believer!

The late Ed Southwick did controlled experiments with whole colonies of
bees placed in environmental chambers.  With adequate numbers of bees and
food, they could survive periods of -80 degree C, well over 100 below F.
Typically, he would chill the colonies down for 24-48 hrs before starting
his measurements of their metabolic functioning.  So we know they were
alive.  The only reason for the -80 limit was that was as cold as his
chamber could go.

As a footnote, they needed lots of food at this temperature.

I once had a Postdoc who spent a couple of weeks building an elaborate
model of how bees were removed from an overwintering population.  It looked
very impressive - on some days only a few bees died, on others, they
dropped in bunches.  Curious as to how he developed this scheme, I asked
and he responded that he modeled die-off as a function of temperature.
Wrong!  Doesn't work that way.  Since the post-doc was a bit stubborn, I
had to pull out Ed's work to set him straight.

Amazing animals.

Jerry

P.S.  We also know that tracheal mites can survive periods of up to several
days in a frozen dead host at -20 C!  We did the tests some years back.
Tough little beasties.  They didn't do so well when the dead hosts rotted
with no live hosts to move to.  So, bad news, you can't chill off Tracheal
Mites, good news, if all your bees die, so will the mites as soon as it
warms up.