Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Please place treatment free research here. There's a lot of research spread around the Internet that is related to treatment free beekeeping. This forum is an effort to try and consolidate some of this, especially new research as it becomes available.
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GregV
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Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby GregV » Tue Oct 03, 2017 3:33 pm

Abstract:

In the absence of human intervention, the honeybee (Apis mellifera L.) usually constructs its nest in a tree within a tall, narrow, thick-walled cavity high above the ground (the enclosure); however, most research and apiculture is conducted in the thin-walled, squat wooden enclosures we know as hives. This experimental research, using various hives and thermal models of trees, has found that the heat transfer rate is approximately four to seven times greater in the hives in common use, compared to a typical tree enclosure in winter configuration. This gives a ratio of colony mass to lumped enclosure thermal conductance (MCR) of less than 0.8 kgW−1 K for wooden hives and greater than 5 kgW−1 K for tree enclosures. This result for tree enclosures implies higher levels of humidity in the nest, increased survival of smaller colonies and lower Varroa destructor breeding success. Many honeybee behaviours previously thought to be intrinsic may only be a coping mechanism for human intervention; for example, at an MCR of above 2 kgW−1 K, clustering in a tree enclosure may be an optional, rare, heat conservation behaviour for established colonies, rather than the compulsory, frequent, life-saving behaviour that is in the hives in common use. The implied improved survival in hives with thermal properties of tree nests may help to solve some of the problems honeybees are currently facing in apiculture.

https://link.springer.com/article/10.10 ... 015-1057-z

(I don't feel like spending $40 for the original manuscript; so far did not find a free download yet).

PS: basically, need to put bees back into normal living conditions first....
then address any issues if any still left
(outside of poisoning them with pesticides, should be no issues left to speak of)

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby moebees » Tue Oct 03, 2017 6:55 pm

Interesting and thanks for posting Greg. It will probably become available after a few months.
Sam Droege, a biologist for the U.S. Geological Survey—“bees are not optional."

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby Varroa Apiary » Sun Oct 22, 2017 6:48 am

There is another link in google with full article for free. Interesting.

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby SiWolKe » Sun Oct 22, 2017 8:03 am

MMh,
I´m just now observing two colonies which are survivors from commercial hives having swarmed and are located in stone walls in shady and cold places with so much space inside the walls to build comb which could be 5m long.
Lets see what are the surviving traits but nobody will reduce space there and warmth must be kept by the cluster alone.
Also there is not much microfauna and flora except what the bees themselves produce.
In the first pict. the entrance is 6m high directly near the yellow flowers ( my tele was not good enough to show the bees entering).

W 2.jpg
W 2.jpg (531.18 KiB) Viewed 208 times


W 1.jpg
W 1.jpg (258.66 KiB) Viewed 208 times
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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby GregV » Sun Oct 22, 2017 4:21 pm

Varroa Apiary wrote:There is another link in google with full article for free. Interesting.


What are the google search words?
I looked for long time and could not find the entire article for free.

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby GregV » Sun Oct 22, 2017 4:38 pm

SiWolKe wrote:MMh,
Lets see what are the surviving traits but nobody will reduce space there and warmth must be kept by the cluster alone.


As long as they have very solid "ceiling" above the nest that prevents the heat loss upwards (the most critical), they may do OK in your locality.
I know of two factual incidents when they wintered fine (my own cut-out and a video from Ukraine I watched).
Leo Sharashkin reports a case of bees a cave in Montana where they have been living for many years (decades, in fact). But the exact configuration of the cave is important, obviously.

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby Varroa Apiary » Mon Oct 23, 2017 5:27 pm

GregV wrote:
Varroa Apiary wrote:There is another link in google with full article for free. Interesting.


What are the google search words?
I looked for long time and could not find the entire article for free.


Here You are
https://link.springer.com/article/10.10 ... ccess=true

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby GregV » Tue Oct 24, 2017 3:50 pm

Varroa Apiary wrote:
GregV wrote:
Varroa Apiary wrote:There is another link in google with full article for free. Interesting.


What are the google search words?
I looked for long time and could not find the entire article for free.


Here You are
https://link.springer.com/article/10.10 ... ccess=true


Unless I am missing something obvious (happened before), this is the same short abstract I posted originally.
It may come from different sites, but the essence the same - short abstract, not a full article.
I am not yet ready to pay a full book price (~$40) for an article.

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby Varroa Apiary » Wed Oct 25, 2017 1:05 pm

Strange. I see full article. :( after tommorow i could try copy this text here

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby GregV » Wed Oct 25, 2017 2:12 pm

Varroa Apiary wrote:Strange. I see full article. :( after tommorow i could try copy this text here


Please!
If you have access to the entire PDF, just post it up.
It will be greatly appreciated.

I suspect this has to do with the regions we are coming from.
The web site senses our origin in Poland and gives you full free access, but yet forces me to pay because I come from the US. :roll:
Happens all the time due to regional discrimination.

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby Varroa Apiary » Mon Oct 30, 2017 12:40 pm

Sorry Greg. Now I can't read full article as You.
But I have copied most interesting fragments for me before.

Here You are.

Ratios of colony mass to thermal conductance of tree and man-made nest enclosures of Apis mellifera: implications for survival, clustering, humidity regulation and Varroa destructor
International Journal of Biometeorology
May 2016, Volume 60, Issue 5, pp 629–638 | Cite as
https://link.springer.com/article/10.10 ... ccess=true

The biological consequences are that for high MCR enclosures such as trees, honeybees will maintain mobility well into winter. However, should the honeybees be provoked to cluster by extreme weather or long periods of darkness, it will take significantly warmer weather outside the enclosure to break the cluster. This behaviour is well suited to coping with long-lasting extreme events by ensuring that the bees do not start to expend energy at higher rates until good weather has been well established. However, it should be recognised that the high heat capacity of the tree enclosures will also greatly increase hysteresis as the bees will be storing significant amounts of energy in the fabric of the tree. This is a topic for further research.

Equation 1, for a given nest temperature and its metabolic rate, shows the relationship between external temperature (Texternal) and the ratio of colony mass to lumped enclosure thermal conductance ((McolonyΛenclosure)(McolonyΛenclosure)) i.e. MCR.

In enclosures, with entrances only in the lower part, the buoyancy of water vapour in dry air and the generation of heat and water vapour from honeybee metabolism ensure that the nest humidity is limited by the temperature and vapour permeability of the enclosure walls. The honeybees coat the inside of the enclosure with propolis derived from tree resins (Seeley 1985) which have very low water vapour permeability (Hagenmaier and Shaw 1992) and form a vapour barrier. This implies an accumulation of water vapour in the top of the nest limited only by the enclosure wall temperature. For example, wall temperatures of 30 °C would enable a nest relative humidity (RH) of 90 % at 34 °C. Previous workers in this field, with Apis mellifera scutellata (Human et al. 2006), have overlooked the dehumidification effect of the condensing, cool surface of the high conductance walls. Their low results of typically 40 % RH may be explained by air with water vapour at 34 °C, condensing on a hive wall at its dew point temperature of circa 19 °C (Lawrence 2005).

Kraus and Velthuis (1997), investigating the causes for lower varroa (V. destructor) breeding success in the tropics (de Jong et al. 1984), described that in three test series with a total of 127 brood cells kept at 79–85 % RH on average, only 2 % of the mites produced offspring, whereas with a total of 174 brood cells kept at 59–68 % RH on average, 53 % of the mites produced offspring. This demonstrated that high nest humidity results in very poor varroa breeding success. In contrast, higher humidity has been shown to improve survival in Apis mellifera carnica and A. mellifera jemenitica (Hossam 2012) and improves egg viability (Doull 1976). It has been shown to be only a minor factor in chalkbrood disease (Ascophaera apis), with an effect of an order of magnitude less than a lowered temperature (Flores 2011), indicating that a highly insulated nest with high humidity would result in markedly reduced chalkbrood incidence but not its elimination.

Huang (2012) has also observed the varroa breeding failure phenomenon and commented “If there are ways to artificially increase the hive RH to about 80 %, then the varroa mite population will never increase to a damaging level”.

"From the discussion above, we can see that, with a high MCR, very high nest humidity can occur in the air surrounding the nest at normal brood temperatures, in cool external conditions (e.g. MCR ∼4, Texternal ∼10 °C) and does not require the external tropical conditions Kraus and Velthuis referred to in their discussion. The build-up of humidity in an enclosure with a vapour barrier at low conductance has been experimentally demonstrated in passive-house building research (Mlakar and Štrancar 2013).

The implication is that high humidity, as a practical means to control varroa, is now a valid topic of research."

By rearranging Eq. 1, we can see that MCR is inversely proportional to the heat loss per honeybee per degree centigrade of temperature difference between the inside and outside of the enclosure, i.e. WK−1 bee−1. Thus, the MCR is inversely proportional to the thermal stress on the honeybees in the nest, which their various coping behaviours must overcome. It should be noted that stress is named as a key factor in various honeybee parasites and diseases (Mayack and Naug 2008; Even et al. 2012).


For researchers wishing to understand the behaviour where the honeybees have greater control of their temperature, humidity and heat expenditure and may exhibit more energetic behaviours, this research indicates that the honeybees should be placed in a nest with shape and insulating material that yields a Λenclosure of 0.5 WK−1, a value equivalent to a typical tree enclosure. The colony should also have sufficient mass to generate a MCR value that will place the colony well into the region of clustering hysteresis, i.e. 2 kgW−1 K or greater.

The energy expended within the nest maintaining homeostasis of temperature and humidity is governed by the fundamental physical principle of the conservation of heat and mass. Quantitative knowledge of heat transfer from the nest to the outside environment through the enclosure is therefore essential to the understanding of homeostasis and other energy-intensive behaviours such as honey ripening. The quantity, a colony mass-to-thermal conductance ratio of the enclosure, fills in a missing piece in the understanding of the heat transfer from the honeybee nest and related processes
.

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Re: Derek Mitchell - Ratios of colony mass to thermal conductance of tree and man-made nest enclosures ....

Postby GregV » Mon Oct 30, 2017 4:09 pm

Cool, thanks.

So, basically, this may be a re-confirmation of a simple man theory - "give the bees a good hive; they will take care of the rest".


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