Bob & Liz wrote:

> Many do not realise hives are wrapped to prevent rapid changes in
> temperature inside the hive. When the temperature drops fast bees can get
> cought away from the cluster. In northern areas (Canada) temps can drop
> 20-30 degrees in short order.

Bob hit on the main reason for wrapping. Not so much for heat in the
dead of winter but a uniform temperature in the hive on both ends of the
season.

>Also tests show that bees move around in
> wrapped hives at lower temperatures than unwrapped hives. They also use less
> stores in the articles I have read.

Both because of uniform temperatures in the hive.

I do not wrap, but if you do it does not take much, usually tarpaper is
enough. Tests showed more substantial wrapping made little difference in
winter survival or spring vigor (the Hive and the Honey Bee). I know two
beekeepers in my area that wrap with tarpaper and one has excellent
success overwintering, the other has more winter kills than those that
do not wrap. The beekeeper's summer and fall practices make a bigger
difference in overwintering and bee vigor than wrapping.

Bill Truesdell
Bath, ME