What do Bees do in the winter cold? 

What do Bees do in the winter cold?
Here in Sweden, it can be minus 25 Deg. C outside and sometimes down to minus 40 deg C for a few days. This is no problem for the bees. The bees cluster into a ball around the queen, rather like penguins in Antarctica. The center temperature is 34 Deg. C ( if there is brood). The ones on the outside move inwards the inside bees move outwards, they share warmth. Using honey stores as fuel, some “Heater Bees” use their wing muscle to produce heat. The honeybee has 2 pairs of large indirect flight muscles that change the shape of the thorax, this causes the wings to beat up and down. In flight one pair contacts as the other pair relax. When “Heater Bees” produce heat, both pairs contract together then relax together. So they don’t actually beat their wings but produce heat, this raises their body temps to 44 C, which is about 9 degrees higher than their usual body temperature. Bees at the outside of the ball act as insulation. If a bee’s body temperature drops below 5 C it dies. I sometimes see photos of hives wrapped up to keep them warm. In our experience cold even intense cold is not a problem, however, lack of ventilation and condensation are a serious problem. Snow is a great insulator but we do also use rigid polyurethane foam hive bodies, depending on the type and quality these can last between 5 to 20 years and are considerably lighter to lift than wood.

We have a friend in Estonia who is manufacturing an innovative new wooden hive called “thermowood” that is especially fired with a Japanese procedure. This procedure renders the wood with an insulation value the same as the rigid polyurethane foam hive bodies with the additional qualities of lasting 50 years not needing any paint or other treatment and being very hard and super strong also looking very fine.  http://www.kablimaa.net/