Winter Cluster Temperature

[cpekarek]

This Winter Cluster Temperature study was measured on hives in Madison, Wisconsin https://naldc.nal.usda.gov/naldc/download.xhtml?id=CAT72345678&content=PDF 

I found this notation on page 12 to be interesting.

On January 4
between 0700 and midnight when the outside
temperature was between 2? and 9? F., the
cluster moved sideways and down into the
center body (fig. 6, L, iV, P). Then it returned
to its original location. Apparently it moved
to obtain honey. This demonstrates how a
strong colony can move its stores under low
temperature conditions. Weaker colonies might
starve with honey in the frame next to the
cluster, because the bees are unable to generate
enough heat to let the cluster spread over
additional comb

[bwallace23350]

Interesting but how to tell if you have a strong or weak hive?

[GSF]

BW, The number of bees. I kind of picked up from other post that it probably has something to do with genetics. Some bees still cluster at 45 other fly at 30.

[Acebird]

Some bees still cluster at 45 other fly at 30.

The bee must first get its muscles up to temperature before it can fly.  If you took a single bee out in 30 degree weather it could not get its flight muscles warm enough to take off.  In the hive it can be wormed by the cluster and then take off and fly through 30 degree air.  For how long I don't know but usually this condition is suicide where the bee intends to die anyway trying to protect the hive from attack or get away from the hive because it is sick.

[BeeMaster2]

Good read CP.

[Jim134]

Some bees still cluster at 45 other fly at 30.

The bee must first get its muscles up to temperature before it can fly.  If you took a single bee out in 30 degree weather it could not get its flight muscles warm enough to take off.  In the hive it can be wormed by the cluster and then take off and fly through 30 degree air.  For how long I don't know but usually this condition is suicide where the bee intends to die anyway trying to protect the hive from attack or get away from the hive because it is sick.

   Individual bees have got to be around 91F to fly. This is minimum temperature. I do not know the maximum temperature.

      BEE HAPPY Jim 134 :)

[Acebird]

http://jeb.biologists.org/content/jexbio/135/1/109.full.pdf

Bees cannot use flight muscles
at temperatures below 10C, even for shivering.

10C = 50F
Towards the end under "Behavioral Observations".

[Cedar Hill]

"How can you tell in winter that you have a strong hive?" I imagine by the color gradients of the cluster shown of the screen.     OR by just listening to them.   Use a stethoscope and give the hive a good rap on its side.   By positioning the instrument on the supers one can tell where they are and by their "roar" whether they are "strong" or "weak".    If they are weak, open them up, drizzle honey on the cluster and add honey frames if needed or sugar on the inner cover you might save them.    If you're really "bothered" by having your bees lying "dead" on the snow, just pick them up, warm them up in your hand, breathe on them and once revived, let them go.   Your kids will love it.   OMTCW 

[mtnb]

   Individual bees have got to be around 91F to fly. This is minimum temperature. I do not know the maximum temperature.

      BEE HAPPY Jim 134 :)

I was watching that Nat Geo video recently where japanese honey bees literally cooked an asian hornet to death. It said their maximum temperature tolerance was 118*F and the hornet's upper limit was 115*F. The honey bees heated the cluster to 117*F. That's for the japanese honey bee but I bet it's similar for their european cousin.