Insulation?

[gmonag]

Olszewski , K. (2007) Winter-hardiness of Buckfast bees under specific weather conditions of areas with alternating influences of maritime and continental climate. Journal of Apicultural Science 51(1), 73-82 2007
Olszewski reported winter food consumption [in kilograms] per colony between 1 November and 21
March (141 days) in Poland by Buckfast and Norwegian x Caucasian bees exposed to different
overwintering methods (data from 2004 and 2005 winter were pooled together). Data from his Table 4 are
shown here:

Overwintering method	Buckfast​	Norwegian x Caucasian​
Mean​	CV​	Mean​	CV​
Uninsulated	11.72​	3.01​	9.7​	15.03​
Insulated	9.72​	17.63​	7.8​	25.59​

Taking the average of the breeds, the consumption rates were 0.076 kg/day for uninsulated hives and 0.062
kg/day for insulated hives. In the study period, minimum temperatures ranged from +1 to -7°C. From the
maximum and minimum temperatures given for November to February the average was calculated as
0.43°C.

Thanks JBM

Unfortunately the Table is corrupted and gives erroneous data. Here is an image from the paper

This study was to compare the overwintering of Buckfast bees with Norwegian/Caucasion cross bees in East Poland. It does indicate that bees the kept in insulated hives used fewer stores than the same bees in uninsulated hives in that climate. Very good.
However my assertion was that clustered bees use fewer stores than active bees (in a winter situation). I don't think this paper helps with that.
I would like to drop this now.

 

[Nannysbees]

Yes.... on both. I use electric fences around my bee yards for both black and grizzly bears. Woodpeckers luckily don't care about my hives (last 8 years).

How amazing, bears

 

[yukonbees]

Greg,

What I was trying to explain in my 1st post. Bees have 2 options for survival under cold conditions. One is behavioural (clustering) (emergency) and the other is to "naturally" use their hive enclosure (primary) to protect them from the environment. The enclosure can protect the bees from extreme cold if the cavity can provide enough thermal protection (R-Value).
There are 3 key variables:

• Size of cluster (heat generation - Passive or Active)
• Size of Enclosure (interior volume - how much space that needs to be heated)
• Enclosure R-Value (capacity to retain heat - reduce thermal loss)
• Other variables: quantity of honey (thermal mass), type of ventilation, leaky seams...

Here are 2 scenarios:
1) Wooden hive, in a double brood format, with 18 frames of bees (Emergency survival mode driven by cluster behaviour)
Bees will passively release heat and enclosure will retain some of this heat. As temperatures drop, heat loss will be larger than passive heat released from the bees. At some point they will need to contract into a cluster to slow down this heat loss. As the temperature continues to drop, some of the bees will need to actively generate heat to keep themselves and the cluster warm. This behaviour seems to be driven by the bee's local temperature. (Self organizing cluster). Each bee's feedback system adjust to local conditions.
Variations to this scenario - a small volume with large number of bees would likely cluster at slightly cooler Tout due ratio of bees to volume. A small cluster would need to cluster at higher Ts.
2) Insulated hives (Primary survival driven by enclosure properties)
The high R value means that the bees will be at resting metabolic rate at lower temperatures before they need to cluster and start actively generating heat to maintain survivable conditions.

Active metabolic rate (shivering) >> Passive metabolic rate (no shivering = resting metabolic rate) (see chart) and look up the referenced paper. Also read up on self organizing cluster behaviour - it is very fascinating.

 

[Amari]

Thanks JBM

Unfortunately the Table is corrupted and gives erroneous data. Here is an image from the paper
View attachment 24994

Phew, glad you pointed that out. I couldn't understand JBM's table and was trying to pluck up courage to say so. I'm always reluctant to appear a fool on this forum....

BTW, I wonder why the variation coefficient (presumably this means the spread of results from lowest to highest) is much wider for the insulated hives? I vaguely remember from a brief course on statistics I did in 1963 that it's dodgy to compare populations with unequal variability.

 

[gmonag]

Greg,

What I was trying to explain in my 1st post. Bees have 2 options for survival under cold conditions. One is behavioural (clustering) (emergency) and the other is to "naturally" use their hive enclosure (primary) to protect them from the environment. The enclosure can protect the bees from extreme cold if the cavity can provide enough thermal protection (R-Value).
There are 3 key variables:

• Size of cluster (heat generation - Passive or Active)
• Size of Enclosure (interior volume - how much space that needs to be heated)
• Enclosure R-Value (capacity to retain heat - reduce thermal loss)
• Other variables: quantity of honey (thermal mass), type of ventilation, leaky seams...

Here are 2 scenarios:
1) Wooden hive, in a double brood format, with 18 frames of bees (Emergency survival mode driven by cluster behaviour)
Bees will passively release heat and enclosure will retain some of this heat. As temperatures drop, heat loss will be larger than passive heat released from the bees. At some point they will need to contract into a cluster to slow down this heat loss. As the temperature continues to drop, some of the bees will need to actively generate heat to keep themselves and the cluster warm. This behaviour seems to be driven by the bee's local temperature. (Self organizing cluster). Each bee's feedback system adjust to local conditions.
Variations to this scenario - a small volume with large number of bees would likely cluster at slightly cooler Tout due ratio of bees to volume. A small cluster would need to cluster at higher Ts.
2) Insulated hives (Primary survival driven by enclosure properties)
The high R value means that the bees will be at resting metabolic rate at lower temperatures before they need to cluster and start actively generating heat to maintain survivable conditions.

Active metabolic rate (shivering) >> Passive metabolic rate (no shivering = resting metabolic rate) (see chart) and look up the referenced paper. Also read up on self organizing cluster behaviour - it is very fascinating.

Yes, thank you. Nothing there I didn't know already. There is also nothing there to contribute to the discussion I was trying to have (which is now over)

 

[gmonag]

Phew, glad you pointed that out. I couldn't understand JBM's table and was trying to pluck up courage to say so. I'm always reluctant to appear a fool on this forum....

BTW, I wonder why the variation coefficient (presumably this means the spread of results from lowest to highest) is much wider for the insulated hives? I vaguely remember from a brief course on statistics I did in 1963 that it's dodgy to compare populations with unequal variability.

It is the same as relative standard deviation (RSD)
Coefficient of variation - Wikipedia

 

[Finman]

Even if he did lose all his bees over winter and got just about everything else wrong ...

 

[Finman]

I have never done this before, says the video author.

I Can say that nobody in Finland uses that solution.

 

[Boston Bees]

I have never done this before, says the video author.

I Can say that nobody in Finland uses that solution.

Americans are the last people on earth I would take advice on beekeeping from.

 

[Amari]

It is the same as relative standard deviation (RSD)
Coefficient of variation - Wikipedia

Thanks. Way above my head! Is it dodgy to compare populations with unequal variability?

 

[gmonag]

Thanks. Way above my head! Is it dodgy to compare populations with unequal variability?

I don't know. It is required to state the SD when plotting data but I don't know what conclusions can be drawn from it in this case.

 

[Finman]

It is the same as relative standard deviation (RSD)
Coefficient of variation - Wikipedia

Known too with name Gauss curve .
When you see the grafic, you understand better those deviation things.

And the meaning of statistics is to make too complex phenomenoms easier to understand.