Hello All,
At this time of year "good" beekeepers should be tending to their bees
rather than pondering theories.  Sometimes I do my best thinking while I am
doing bee work.  (There is something a psycho-analyst can spend days on.)
As with all theories if you throw them around enough sooner or later you
will find someone to agree with you.

Disclaimer:  This post is probably going to be a rambling of thoughts that
have been going through my head the past few months (being driven by the bee
loss I had this winter) trying to answer questions that start with "why".
Some I have answers, others I am not too sure.  Hopefully, you will also
ponder these and come up with your own thoughts or ideas.

Observation:  I maintain an observation hive at a nature center.  It was
built BM (before mites) so the design does not allow for easy treatment.  I
had trouble keeping it going for a few years (mid '90's) but now it has been
up and running for almost two years without any treatment.  It has a
screened bottom with a debris pan underneath.  I have not seen any varroa in
the pan.  This colony is doing well on its own.  WHY?

Observation:  I lost colonies this winter.  Some were due to Apistan
resistant varroa.  Some probably to tracheal mite (TM).  But I still have
problem blaming it all on mites.  Colonies that were protected from wind
survived much better than those in the open.  Somewhere in the back of my
head the weather keeps jumping into my thoughts.  WHY?

Known fact:  Bees survive in very cold climates, and very warm ones too.  My
climate is neither.  So WHY do I keep going back to the weather issue?

I have no experience keeping bees in very cold or very warm climates, or do
I?  We are seeing 100 F days with 80% humidity in the summer (sounds like
Florida), and 0 F degree days with -30 F wind chill in the winter (Canada?).
Beekeepers will be quick to point out that bees do well no matter what the
weather and my problem is somewhere else.  Possible, however the weather is
changing.  In my area the past few winters were mild.  Bees are flying
around at Christmas.  Ten years ago this was uncommon.  This past winter was
the same but we had severe cold spell.  I lost a number of colonies during
that period.  If a colony has TM and they take a cleansing flight on a "warm
winter day" they may not make it back causing the population to dwindle.
Eventually they cannot maintain cluster temperature and perish.

Theory:  Let's assume there is no mite problem.  What do bees do on warm
days in the winter?  They fly around looking for forage just like they would
any other time.  These are not cleansing flights, and some may fly a good
distance from the colony.  If they do this towards the end of the day the
temp may drop and they may not make it back, causing the population to
dwindle.  If the weather stays mild this may not affect the cluster and they
will survive the winter.  But what happens if this goes on for a month or
two and then a few weeks of really cold weather sets in.  Those smaller
clusters will have trouble surviving.  The whole scenario resembles TM so
the beekeeper writes it off to mites.

A few years back I started switching from Italians to Carniolans.  One
reason was because of the smaller winter cluster and a break in the brood
cycle.  Could this cool weather trait work against them in a warm/cold
winter?

I found someone who agrees with this theory.  Actually he is person who
proposed it, and it fit well with my thoughts and observation.  He mentioned
that in the 12th century bee houses started showing up in Europe.  This
coincided with a warming trend in the climate.  The bee house would keep the
colonies cool on warm winter days and prevent them from flying.  I don't
know much about the history of bee houses but it makes sense.  The honey
flow will not be extended because of warmer winters until plants become
established.  This takes time.  But if you artificially control the climate
keeping things cooler the bees will be less affected.

I am not a weather expert and I can only comment on what I actually observe,
but I think this theory has some merit.  It may only apply to small fringe
areas.  You probably don't want to think about winter at the beginning of
summer, but if you do care to share your thoughts on this I would like to
hear them.  If this is a problem it will be the first one in while that we
won't try to control with a new chemical.  Also, if anyone has knowledge on
the evolution of bee houses, it would prove to be interesting.

Take care,
Ron Bogansky
Kutztown, (eastern) PA, USA