Heat regulation of Apis mellifera during winter

If we compare Apis mellifera and Apis cerana to each other, we see what is important in winter surviving.

I did not find now the reseach from Japan city bees A. cerana. They prefer make the hive in open air and only 20% of free colonies are in cavity.

Cerana maintains 36C cluster temp the whole winter.

What in the heck I thought. Where is Japan? Japan is ate the same level as North Africa and south half of Mediterennin sea.

Apis mellifera got a habit to make a hive in tree holes. The cavity gives shelter from enemy and prptects the colony from wind and cold.

I started with unsinsulated hives 48 years ago and I know how much less the hive consumes in insulated hives.

I have seen too that after mild winter the food storage is big in hives.

After hard winter it is important to look that food is enough. The starving arrive mostly aftern cleansing fligh in March and April, because colony start to make brood and they rise cluster temp from 23C to 36C.

The spring consumtion of food is really big compared to autumn consumption.

The smaller the colony the more it must work to produce the heat ovet winter.

It is important too to restrict the winterin space to minimum that the heat do not escape to large empty space.

.

Researches:

http://jeb.biologists.org/cgi/content/full/206/2/353

Endothermic heat production in honeybee winter clusters , 2003
Institut für Zoologie, Universität Graz, Universitätsplatz 2, A-8010 Graz, Austria

Summary
In order to survive cold northern winters, honeybees crowd tightly together in a winter cluster. Present models of winter cluster thermoregulation consider the insulation by the tightly packed mantle bees as the decisive factor for survival at low temperatures, mostly ignoring the possibility of endothermic heat production. We provide here direct evidence of endothermic heat production by `shivering' thermogenesis. The abundance of endothermic bees is highest in the core and decreases towards the surface. This shows that core bees play an active role in thermal control of winter clusters. We conclude that regulation of both the insulation by the mantle bees and endothermic heat production by the inner bees is necessary to achieve thermal stability in a winter cluster.

Researches

http://www.beekeeping.com/articles/us/colony_temperature.htm

Determination of development periods of honeybee colony by temperature in hive in Latvia, year 2002



Development of the hive tempereture along the year.
The temp is the inner cover surface temp under insulations.
.

exactly what i was saying - heat generation within cluster and insulation on outside.

My hives have dipped as low as 8C and as high as 19C this winter.

.

Researches

Solar heating of hives in Israel

http://www.beekeeping.com/articles/us/solar_heating.htm

Endothermic heat production in honeybee winter clusters

discussion

Resting metabolism — although higher in the core — is not alone the source of the heat that is necessary to compensate for the heat loss (Fig. 1), because there must be some convection in the cluster (either cyclic or permanent) that allows the cluster to get rid of the CO2 produced (Heinrich, 1981; Van Nerum and Buelens, 1997) by both the endothermic bees through shivering thermogenesis and the ectothermic bees according to their resting metabolism.

Southwick (1983, 1988) and Southwick and Heldmaier (1987) showed that the oxygen consumption of winter clusters increases as the ambient temperature decreases. The increase is moderate between approximately +10°C and -5°C and is steep below approximately -5°C to -10°C. In swarm clusters, the steep increase has already started at +10°C (Heinrich, 1981). Oxygen consumption also increases with decreasing cluster size (Southwick, 1985). Therefore, the frequency and intensity of endothermic heat production have to be assumed to increase with decreasing ambient temperature and cluster size. On the other hand, we suggest that at higher ambient temperatures large (swarm) clusters that have come to rest (e.g. at night) may be able to largely reduce endothermy (Heinrich, 1981).

good info Finman, thanks for posting this

.
My heating experiments


I have made heating experiments during 7 years.

Just now I have on colony which has only one frame of bees. 2 night ago temp was on my cottage district -26C. The hive in the firefood shed.

But I have in the nuc 7W infra heater. Bees are not in cluster but they "sleep" on the surfage of the heat capsule. Heater is inside a folded aluminium plate.

When electirict was shut, the cluster was twist size ball a week ago.

Here is one example of small hive heating. This size colony will not survive over our winter, but with heating aid there is no proplems.

.

Heat regulation with snow tunnel


This professional beekeeper has 150 hives. He lives on area where -30C is quite common. He has generated a wintering system wher hives are collected on the field in several snow tunnel.

The temp under snow is about -4C even if the air temp is -30C.

finman you have out done your self again with your research, but what is your opinion on the hives covered in snow , whilst the snow does insulate very well and i can see the ideas behind it ,

what is your opinion on such like as moisture levels inside the snow chamber.

having spent several nights out inside snow accomadation i have always found there to be very high humidity?

hedgerow pete said:

finman what is your opinion on the hives covered in snow

such like as moisture levels inside the snow chamber.

Click to expand...

We have had in Soth Finland during last 20 years under 0,5 metre.
It is not enough to cover the hives.

30 years ago hives were often coved with snow.

A diffenrec with my area and that "snow tunnel man" is that we have often wet snow and over freezing temperatures. When the snow is wet, bees clearly suffer from moisture compared with situation that snow do not rise to level of entrance.

having spent several nights out inside snow accomadation i have always found there to be very high humidity?

Click to expand...

If we think about iglu. the heat melts the snow and you are practically surrouded with film layer of water. It is humid.

On another hand, when temp is very low, air is very dry. When cold air is heated up like in the car, air becomes very dry and you feel it in your nose.
But it means from -20C to +15C.

During snow outside relative moisture is all the time over 90%. When it is heated to room temperature, relative moisture is about 20%.

.

.

Winter cluster. Outside temp is about zero C.

a tight form tells that they have brood and they protect the brood temperature.

Later a brood produces as much heat as a resting worker.

Really interesting finman... Do you purely use the heaters for experimental purposes or do you use them often to help nuc's and weak colonies get through winter?


Ben P

ben.pullan said:

Really interesting finman... Do you purely use the heaters for experimental purposes or do you use them often to help nuc's and weak colonies get through winter?


Ben P

Click to expand...

I use heater only to fasten spring build up during April-May. I have done it now 7 years.

The best advantage comes to the biggest hives together with pollen patty feeding.

I try that I have not weak colonies over winter. They makes only trouple.
It is quite easy to make all hives or join weak ones so that they are normal one box colonies.

In winter I have 20% extra colonies. If something happens, I do not cry after them.