# Derek Mitchell article discussing effect of higher humidity on varroa



## clong (Apr 6, 2015)

Derek Mitchell has another research article that addresses hive configuration and its impacts on humidity. Apparently, it also covers the implications of higher humidity on varroa reproduction.

https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0048

From the abstract:

"It is highly likely that honeybees, in temperate climates and in their natural home, with much smaller thermal conductance and entrance, can achieve higher humidities more easily and more frequently than in man-made hives. As a consequence, it is possible that Varroa destructor, a parasite implicated in the spread of pathogenic viruses and colony collapse, which loses fecundity at absolute humidities of 4.3 kPa (approx. 30 gm−3) and above, is impacted by the more frequent occurrence of higher humidities in these low conductance, small entrance nests."


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## GregB (Dec 26, 2017)

clong said:


> Derek Mitchell has another research article that addresses hive configuration and its impacts on humidity. Apparently, it also covers the implications of higher humidity on varroa reproduction.
> 
> https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0048
> 
> ...


Possibility of CO2 and/or humidity being a factor is often mentioned.
For sure, bees in the trees have much better control of both as well as higher presence of both (vs. the commercial hives, since we are so crazy about "ventilation").
One reason I really want to trial a Warre-formatted hive, but built similar to this:
https://www.youtube.com/watch?v=tV90sHPOd70


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## Litsinger (Jun 14, 2018)

GregV said:


> One reason I really want to trial a Warre-formatted hive, but built similar to this:
> https://www.youtube.com/watch?v=tV90sHPOd70


Interesting video, GregV. Initially I thought we were looking at thin-walled hive bodies but then I realized that the top super had a rabbet along the whole perimeter of the box to receive the plastic? inner sheeting. Also it may be based on the width of the top bars, but it looks like his frame spacing is wider? Maybe 1-1/2" center-to-center?


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## GregB (Dec 26, 2017)

Litsinger said:


> Interesting video, GregV. Initially I thought we were looking at thin-walled hive bodies but then I realized that the top super had a rabbet along the whole perimeter of the box to receive the plastic? inner sheeting. Also it may be based on the width of the top bars, but it looks like his frame spacing is wider? Maybe 1-1/2" center-to-center?


Unsure of his center to center.
Pretty sure standard 35mm (1-3/8).
The top bars, however, are metal pipe about 1/2 inch - this allows for pass-thru up and down.
These thin top bar create an illusion of wider frame (the are not really).

He has two hive formats:
* 12 frame (the original format)
* 8 frame (this one the author favors now as he is an older dude).

The box walls are compatible to our 2x wood.

The clear heavy plastic completely seals the top.
Lately he switched to using clear silicon film, actually - a great idea.
I think this material is like silicon rubber and thinking get some and test it.
Check it out - great specs, about ideal:
https://www.amazon.com/Silicone-Rub...ocphy=9018945&hvtargid=pla-441001201172&psc=1


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## GregB (Dec 26, 2017)

More vids of the same - just observe the heavy film/silicon.
The hives come out of winter:
https://www.youtube.com/watch?v=QrkSnEjYBng
https://www.youtube.com/watch?v=OV0gcwb7HKo


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## GregB (Dec 26, 2017)

8-frame square; 
silicon completely seals the top; 
metal plate - helps to condense the water by cooling off the seal - this is early summer and condensation is very good help for brood rearing;
notice how bees do NOT propolise the film between the combs - NOT needed - the non-permeable seal is already in place
https://www.youtube.com/watch?v=WLduRE96S_U

PS: the propolise pushing researchers should watch this video and think - WHY is it bees not propolising the film over the brood nest???
because it is NOT needed and they will not spend the time/effort doing it if the surface is already satisfactory in sealing the nest
Yes - very unhealthy - no propolise ..... - I am being sarcastic now.

For this exact reason they will propolise my burlap completely - to seal it closed.


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## Litsinger (Jun 14, 2018)

GregV said:


> I think this material is like silicon rubber and thinking get some and test it.


GregV:

Thank you for your reply. I do hope you give this a try and let us know how it works out for you. I for my part am still hesitant to incorporate anything that is vapor impervious in my hives, but watching CLong's success with his highly insulated assemblies makes me want to dip my toes in the water and give it a try- at least on the top.

Thanks again for the response- I do appreciate it.

Russ


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## clong (Apr 6, 2015)

Litsinger said:


> GregV:
> 
> I for my part am still hesitant to incorporate anything that is vapor impervious in my hives, but watching CLong's success with his highly insulated assemblies makes me want to dip my toes in the water and give it a try- at least on the top.


Russ,

I can understand your hesitance to create a vapor barrier in you hives. It goes against conventional wisdom. But it is done the world over, including in feral colonies. In fact, in Tom Seeley's latest book, he suggests that having a sealed hive with only a lower entrance is beneficial to the colony especially when water is needed in the winter.

I wouldn't call my efforts "success". When I see 80% survival rates, and 100 lbs of honey/hive, then I will start to celebrate.


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## Litsinger (Jun 14, 2018)

clong said:


> I wouldn't call my efforts "success". When I see 80% survival rates, and 100 lbs of honey/hive, then I will start to celebrate.


CLong:

I for one applaud your efforts and it seems to me that you are moving in a direction which has been more successful year-over-year. That is progress!

Your efforts and results have convinced me to at least increase the resistance of the roof assembly as a start, so I am listening.

Keep up the good work, and thanks for sharing your experiences here for the rest of us to learn from.

Russ


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## clong (Apr 6, 2015)

clong said:


> Derek Mitchell has another research article that addresses hive configuration and its impacts on humidity. Apparently, it also covers the implications of higher humidity on varroa reproduction.
> 
> https://royalsocietypublishing.org/doi/10.1098/rsif.2019.0048
> 
> ...


The full article:

https://eprints.whiterose.ac.uk/146484/1/whiterose22052019.pdf


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## Swarmhunter (Mar 5, 2015)

There is an article in the Feb.-ABJ by Bill Hesbach on ventilation of the Condensing Colony that ties in nicely with these articles about high humidity and varroa control. It definetly has changed my view of top and bottom ventilation- especially for Winter. Makes you think about the old rules of top and bottom ventilation.
I'd like to hear others views.
Jerry


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## Litsinger (Jun 14, 2018)

Swarmhunter said:


> I'd like to hear others views.


Jerry:

Good post- I saw their is an accessible online article from Mr. Hesbach here:

https://www.beeculture.com/winter-management/

For my part I have a mix of standard Langstroth hives that I run with a top entrance consisting of a single 1" diameter hole and Warre hives with a single 7/8" diameter hole in each and every box.

I have found that in preparation for Winter all colonies will work to partially occlude the openings but rarely close them off completely.

Further they seem to be constantly working on the openings, adding and removing the propolis plug as overwintering progresses.

Based on this completely anecdotal feedback I've concluded that they know what they want and I let them open or close the openings as they see fit.

It also does appear that they tend to utilize the upper entrance preferentially for cleansing flights in the Winter, so there might be some marginal benefit there.

What do you observe in your locale?


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## Swarmhunter (Mar 5, 2015)

I'm in the process of converting my timetable to be OTS freindly. I'm also reconfiguring my hives to be closer to natural beehives. More insulation summer and winter and entrances on the sides , half way up. no upper or lower entrances. I really think the bees will thank me.
Way to much cold wet dripping on bees the way we've been ventilating. Going to change some things
Jerry


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## Robert Holcombe (Oct 10, 2019)

I have not had a duel vent hive in three years; choosing to have a bottom vent only. I have been trying for several years to define the design requirements for an enclosure for honey bees. "Homeostasis", year round, sums all the issues in a neat definition. Defining the variables is not easy but I think I am approaching a new level - seeing homeostasis within a hive - but still have a lot to learn. I need more sensors in more hives. Existing data out there helps a lot, leap-frogging doubts, when I know how to ask a question of Google Scholar; Seeley, Mitchell, Ellis,Tautz, Mobus all have a lot to offer. Hesbach offers some good explanations.

My trend is simply emulation of typical tree hive characteristics but larger volumes, different materials. Do not underestimate the effect of wind on heat transfer, both convective heat transfer coefficients and tidal / mass flow effects. I am becoming a believer in conservation of water within a hive and buffering characteristics. I don't like plastic only nor more vents, propolis is amazing. Observation: It is amazing how fast moisture leaves a hive when it is cold and dry outside - my bees forage for water anytime it is above 40F and sunny, sometimes grey skies (dehydration issues?). I live in a wet area near the ocean and have a lot more to learn, so it seems. Best of luck to all who experiment ( and everyone else) this coming Spring.


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## Swarmhunter (Mar 5, 2015)

Robert-
Sounds like your asking a lot of the same questions a lot of us are pondering. I've got almost all 8 frame equipment and I'm really glad I went that way because of the way I'm thinking of wintering my bees starting next year. Taller , narrower, better insulated, a3-4 inch deep area between the bottom board and brood area and only one entrance - 1x3 inches-- half the way up the hive into the brood area. Radical? Not according to mother nature.Top- heavy insulation with a short spacer for natural air circulation and patty feeding. Natural warm air of the hive will circulate across the top and down the sides for condensation on the sides instead of dripping from top.
Just my ideas for next winter. Sick of losing bees (7 this winter). Going to do a lot of things different the next 6 months
Jerry


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## Robert Holcombe (Oct 10, 2019)

Jerry: I cannot comment on 8 frame versus 10 except form a concept point of view. Horizontally there is less insulation but that is easily accounted for by sizing insulation. I put a 2 inch spacer on top of my propolized 12 oz. duck cloth - inner cover . I put my remote sensor here on the canvass. I also loosely pack in some old cotton tee-shirts. ( Shades of a quilt box approach but no direct venting) I soon realized I have created some sort of" tree like" topping. I have watched water collect on the top canvass, eliminated that issue and then the I have watched the RH change slowly with ambient weather. RH is always high in this top zone but temperatures just below the dew point - a controlled water vapor buffer zone? It is also very curious that the colonies have raised the canvas on short, top bar columns of waxy propolis providing circulation like passage ways, I think. 

I feed heavily in the Fall to "weight" ( see M. Palmer). I am going to modify by canvass inner cover by adding a central hole to allow emergency or early Spring syrup feeding if necessary. It will also be useful for installing sensors and probing quickly. I currently stick a simple dial thermometer ($5.00) in each hive top canvass as a simple data point and verification the colony is alive.


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## crofter (May 5, 2011)

Delete; off topic


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## LAlldredge (Aug 16, 2018)

I have been feeding water back to my hives since December either through a wet sponge on the landing board or from spritzing their sugar bricks. So while they now have a dry cavity I’m reevaluating the top entrance again if I already have vent holes and vivaldi quilt box. 

Just read the ABJ article. Wondering again how much colony death has more to do with dehydration then starvation aided by hive design. The well known “they were surrounded by honey but couldn’t move” problem. Maybe they couldn’t metabolize their food from lack of water and humidity.


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## Litsinger (Jun 14, 2018)

Swarmhunter said:


> Way to much cold wet dripping on bees the way we've been ventilating. Going to change some things


Good thread, Jerry. It is interesting and helpful to read about how others are approaching this issue. I imagine that the 'right' answer may at least in part have something to do with one's specific climate and weather patterns.

For my part (as previously noted) I run top and bottom entrances on all hives and the bees respond by laying down propolis in varying degrees to the upper entrance in preparation for colder weather (example photos attached) and seem to be continually monkeying with the opening size (with no discernible pattern) throughout the winter. 

This winter (and based on the success of others on this forum), I decided to add 1" closed-cell foam insulation to the colonies for added benefit, with some worry that this might lead to the accumulation of condensation above the cluster.

On one of our recent mild days, I popped the tops and to my joy only found two colonies with condensation on the inner cover- in both cases it was in the corners and not over the cluster, which squares with what I believe CLong has observed with his highly-insulated assemblies.

I do sincerely hope you are able to find a hive set-up that provides reliable condensation control in your locale, and I look forward to reading about your experiments.

Russ


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## Swarmhunter (Mar 5, 2015)

What are you using (how big?) - for an entrance hole and where is it placed. Also what are you using for insulation on the sides and are you leaving it on in the summer?

Jerry


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## Swarmhunter (Mar 5, 2015)

Robert- What are you using for entrance holes -(what size and where?) What are you using for insulation on the sides? You leave insulation on summer and winter?
thanks
Jerry


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## clong (Apr 6, 2015)

Swarmhunter said:


> What are you using (how big?) - for an entrance hole and where is it placed. Also what are you using for insulation on the sides and are you leaving it on in the summer?
> 
> Jerry


3/8" x 4" to 3/8" to 8" entrance reducer.
Last year: 1" rigid foam on sides with 2" under telescoping lid. Also, one Beemax Poly hive.
This year: Some hives will get 2" on sides, with 2" under lid.
All insulation stays on all year long.


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## Robert Holcombe (Oct 10, 2019)

One thing I have learned, invariably it is always more than one issue. One head sometimes rises higher. Maybe they wee not albel to move to warm food. The primary tools of a honey bee are heat generation, fanning and sensors. If honey temperature ( an dinternal ambient) is down, say 25F for exaggeration purposes, how are they going to consume it, get to it? Once bees can establish temperature control in a volume they tailor it to their needs. This assumes no real mechanical issue like an iced covered entrance/exit for days. Once temperature control is established they work hard on humidity control. IMO, those who cannot establish humidity control by foraging for water, raising brood for more water or control moisture losses die of dehydration. I strongly favor a one hole design; bottom is my choice. I "think" ( no data) mid or top is OK but a little more stressful in winter as the cluster needs to adjust. 

Pick up, bare handed, an apparent dead bee outside the hive in cold weather. One that looks perfectly normal but cannot move (I do this to check for diseases occasionally). Sometimes they will start to twitch - a leg, antennae movement. Cusp it for a minute or more and open - you will see more motion. Do it long enough with a little sun and they can fly away. Some go right back to the snow and die ( altruistic suicide due to disease?) . Some head for the entrance or a sunny spot or I place them on an entrance so they can decide. It all starts with head temperature followed by thorax, then abdomen.


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## Robert Holcombe (Oct 10, 2019)

Jerry, My entrance is a bottom mounted vertical, sliding plate with about 7-8 holes big enough for a drone to exit (7/32 -1/4"). This is in conjunction with a bottom screen board with a sticky board (3/8" gap between screen and sticky board in place all winter, most of summer. My side insulation is now 2-inch XPS and the top is now 4-inches think. No top venting but temp and humidity sensors on 3 hives, temp sensor on most hives. I intend, this year, to test full side insulation on ~1/2 of my 9 hives this year with the other half having top insulation only - starting about June 1 after last frost. Hope it helps - it has been a warm, wet winter this year and raining/fog as I type. (A few years ago 6 Ft. accumulation, typically 2 feet but been changing - wide range).


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## Robert Holcombe (Oct 10, 2019)

Clong - "All insulation stays on all year long." Can you offer any observations, positive and negative experiences? 

My casual observation of a poly-nuc is it is a poor moisture buffer and collects water. I also see extra vent holes, front and rear for this type of design (had closed rear but soon opened it). But heat / temeprature control increases brood rearing significantly. I am building wood nucs with glued on XPS foam insulation.


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## clong (Apr 6, 2015)

Robert Holcombe said:


> Clong - "All insulation stays on all year long." Can you offer any observations, positive and negative experiences?
> 
> My casual observation of a poly-nuc is it is a poor moisture buffer and collects water. I also see extra vent holes, front and rear for this type of design (had closed rear but soon opened it). But heat / temeprature control increases brood rearing significantly. I am building wood nucs with glued on XPS foam insulation.



Robert,

I didn't notice anything negative. I never noticed any moisture on the inner cover. I flipped it to the notched side in late May or early June, thinking it would help the bees to remove moisture. This year I plan to keep it shut.

My bees are in 80% shade during spring/summer. I didn't see any mold, or obvious signs of distress in the poly hive. They made 75 lbs of honey, which is my best performer to date.

My question is how do the bees get 100s of pounds of moisture out of the hive? I've never seen any water trickling out. Do the bees carry it out?


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## Robert Holcombe (Oct 10, 2019)

I do have a handle on net pounds of water by method but the primary mode, I think, is the difference in vapor pressure between inside the hive and outside. Basically when the inside is warmer (hot and moist or higher RH) than outside ( cold and dry or low RH), then the hived drives water vapor out via the entrance / vent holes like a water faucet ( likely mixing mechanically and by diffusion, inside with cold dry air first. Moisture vapor also penetrates the wood box walls (permeation) and is stored or lost. You do not see water vapor until it condenses as in a cloud which is water droplets. Fanning, especially in summer time removes moisture from honey or when cooling the hive by causing a flow of moist air out. Pictures tell the story better - Dept of Energy has stuff on house moisture which is the same technique. In winter, I think condensation in the cold zone, below the cluster, also contributes as well as cleansing flights (bees store water in their poop). Wind pressure variations cause what I call "tidal flow" causes air to flow in and out of the entrance ( you fell it on a windy day opening the door you house. Top vents with a bottom entrance have a chimney effect that constantly pulls moisture and heat out of the hive, 24 hours a day - people have reported seeing it condensing at the top vent. 

The more I read, the more is seems that dehydration is the big problem - crazy eh? I have been able to see the effect of moisture loss in a reduction in RH when days are cold with low RH. It is a process that continues for days not minutes and hours. A researcher a the turn of the century saw the effect with simple mercury thermometers and weighting scales. He was trying to measure honey consumption but his data was distorted by hive weight changes due to moisture absorption. Weight would go up sometimes and then drop significantly over a number of days - in winter. Wood is good buffer or storage material for water as it takes and gives back slowly through the propolis layer if the wind does not rob it all. Of course the modes vary with the season; summer, honey, flying bees and lots of brood is a lot different than winter clusters and little brood. 

Hope this helps.


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## clong (Apr 6, 2015)

Robert,

So it is all removed via air exchange? I still can't wrap my mind around it, but I'll chew on it for a while.

Thanks a lot for taking the time to answer my question.


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## Robert Holcombe (Oct 10, 2019)

Mostly airborne from what I can figure out. I cannot give you a number-yet. Bees on cleansing flights are dropping water with the poop but as they fly the loose moisture to the air. It would seem a small amount gets to the ground from condensation and popping. 

To eliminate water from a hive, the hive has to be warmer and more moist then the outside. When it is hot, raining or foggy, and close to or at [email protected]% relative humidity outside during a hot summer day the moisture flow reverses. Uncapped honey will absorb water, wood will absorb water, brood cells will absorb water(brood cocoons), stored it in poop chamber. Fortunately rain usually cools the air below 95F giving the bees some margin to manage with - lots of fanning. I have measured the top of my supers at 99 - 102F, brood chamber is 93-95F rock solid and you can hear the hummmmmmmmmmh. When liquid water evaporates it takes a lot of heat to do it.


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## Swarmhunter (Mar 5, 2015)

Robert- For those of us that are going to insulate-2" on top and sides - and run solid bottom boards - one bottom entrance-- would insulation under the bottom board affect the natural moist air flow down the insides of the hive? Or would leaving the bottom board exposed underneath to the outside temp be ok?
Jerry


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## Robert Holcombe (Oct 10, 2019)

I have not looked at that, insulated bottom nor tested that approach. I am testing no insulation on the bottom becasue I like a cold bottom concept as a water condenser. But, I do no think it, solid bottom , no insulation, is that far different than my current approach of small entrance holes and a screened bottom board with sticky board in place -essentially a cold bottom, no bottom insulation. I can tell you that the air temperature drops as you go down a hive - significantly, even with insulation on the sides. Warm moist air rises and of course clusters in winter are like wood stoves with a pot of water on top. I have an air-gap between the hive boxes and the insulation. A good sized cluster with brood ( I think) will keep the air-gap at 60 F on top and 50 F at the bottom, smaller clusters seem to hold it in the 50F region with mor evariations. How good is the wood stove ? that's the unknown. 

I use to do some testing in an environmental chamber the size of a long shipping container. The moisture generator was about a 3 inch glass tube with a heater and dripping water inside. Being steel, the container did not lose much water vapor. We could control the relative humdity and temperature (40F to 120F) and make it rain. I do not remember a blower ( fanning) on the glass tube, I think is was just diffusion by vapor pressure differentials - like a whistling tea pot or a boiling pot of water. It seemingly only needs a small hole to casue flow - logical!?


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## Swarmhunter (Mar 5, 2015)

Good ideas - I'm pretty sure I know what my insulated cavity is going to look like now. I thank you for your input. I'll let you know how the construction is going. Remodeling older equipment mostly Got part of it done. Will have 12deeps- tops and bottoms and insulated to move some of my bees into this Spring thanks again
Jerry


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## Litsinger (Jun 14, 2018)

Litsinger said:


> For my part (as previously noted) I run top and bottom entrances on all hives and the bees respond by laying down propolis in varying degrees to the upper entrance in preparation for colder weather (example photos attached) and seem to be continually monkeying with the opening size (with no discernible pattern) throughout the winter.
> 
> View attachment 53483


Here's a good example of what I am talking about. The previous photo (above) is of a hive with the upper entrance completely closed off after having it partially open most of the winter.

This week, after a stretch of milder weather, they partially re-opened the entrance for foraging (and possibly environmental control?).


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## crofter (May 5, 2011)

Bumping this up for a review. Lots of good info links spread thru the thread. Some questions answered about insulation staying on year around; No it wont cook your bees! Has anyone seen reports of bad results from people who have tried more insulation and less ventilation? I have not seen much barring my own experience with having hives totally iced in with frozen slush which is a highly unusual situation. Gray Goose may have got hit with the same weather and same bad results.


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## Swarmhunter (Mar 5, 2015)

Hi everyone - it's been a long busy Spring- Summer and Fall. Every time I'd convince myself to sit down and post my current activities something else would demand my attention. This retirement thing can get awfully hectic. 
I did get most of my hives reconfigured into med. - deep - med. - as I wanted last Spring. One round opening in the top of the bottom med. - no top opening and 2" of foam insulation on top. Ended up with 19 put together this way. I lost 12 hives through the winter, last winter, using my old configuration with a small vent hole on the top and bottom.
I then split 10 of the strongest hives in mid-May and sold those Nucs in June. Almost all of the other hives I split into 2-3 and 4 hives and Nucs around the 1st of June. Sold 5 of those Nucs in July. This was all done by producing my own queen cells by several different Queen pulling methods. ( Mel Dissoelkoen). The hives that I split in May all produced 80 - 100 lbs of honey. A few of the other June splits produced an x-tra box too.
All hives - all summer were in med.- deep - med. and supers above that. One small opening in pollen box and 2" foam on top. (Walt Wright) Last Spring I didn't do any checkerboarding (Nectar Management) - I was to busy reconfiguring the hives. Next year- I'm going to try to leave some of my July Nucs for 5 over 5 Nucs and overwinter them that way. All my Nuc boxes are sitting empty in the garage- kind of a waste. I will also be CBing in April.
Treated everything with OA in August after harvest. No high mite counts ( I credit the brood breaks all of my hives had). Will be doing mite counts in Spring and plan on treating high counts. (OA) I also believe that the high temps and high humidity in the hives has helped keep the mite counts low. I don't have the equipment to know that for sure but the majority of my hives looked strong going into winter. All had brood in the central deep and strong stores in the top med. I did feed heavy in Oct. 
So that's been my year along with U-pick strawberries- raspberries and deer hunting. (shot an elk in Wyoming in Sept. ). Expansion year for me. We'll see what Spring brings.
Have a happy and prosperous New Year!
Jerry


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## Gray Goose (Sep 4, 2018)

Swarmhunter said:


> Hi everyone - it's been a long busy Spring- Summer and Fall. Every time I'd convince myself to sit down and post my current activities something else would demand my attention. This retirement thing can get awfully hectic.
> I did get most of my hives reconfigured into med. - deep - med. - as I wanted last Spring. One round opening in the top of the bottom med. - no top opening and 2" of foam insulation on top. Ended up with 19 put together this way. I lost 12 hives through the winter, last winter, using my old configuration with a small vent hole on the top and bottom.
> I then split 10 of the strongest hives in mid-May and sold those Nucs in June. Almost all of the other hives I split into 2-3 and 4 hives and Nucs around the 1st of June. Sold 5 of those Nucs in July. This was all done by producing my own queen cells by several different Queen pulling methods. ( Mel Dissoelkoen). The hives that I split in May all produced 80 - 100 lbs of honey. A few of the other June splits produced an x-tra box too.
> All hives - all summer were in med.- deep - med. and supers above that. One small opening in pollen box and 2" foam on top. (Walt Wright) Last Spring I didn't do any checkerboarding (Nectar Management) - I was to busy reconfiguring the hives. Next year- I'm going to try to leave some of my July Nucs for 5 over 5 Nucs and overwinter them that way. All my Nuc boxes are sitting empty in the garage- kind of a waste. I will also be CBing in April.
> ...


Great feedback Jerry,
I am jelly of the Elk harvest that is still on my bucket list.

hope the spring ends up with lots of strong hives.

GG


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## Litsinger (Jun 14, 2018)

Swarmhunter said:


> Have a happy and prosperous New Year!


Good post, Jerry. Glad to hear all went well this past year.

I sincerely hope that you and your family have a joyous, healthy and prosperous 2022 as well.

Russ


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## david stern (Dec 13, 2021)

crofter said:


> Bumping this up for a review. Lots of good info links spread thru the thread. Some questions answered about insulation staying on year around; No it wont cook your bees! Has anyone seen reports of bad results from people who have tried more insulation and less ventilation? I have not seen much barring my own experience with having hives totally iced in with frozen slush which is a highly unusual situation. Gray Goose may have got hit with the same weather and same bad results.


Now that the honey is extracted and all the queens that did mate and make their way back to their colony are laying, this post seems more relevant again.


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## crofter (May 5, 2011)

I have seen the article by Mr. Hesbach on different forums. Many people successfully take a different approach to ventilation but I have not seen his theories trashed to any extent. There is a vast difference in local conditions experienced by members here, from no winter to 6 months with very few opportunities to fly. For some, winter is not much of an issue.

The more honey the bees have to consume to achieve desired cluster temperature and humidity concerns, the more gut waste they have to hold onto or else soil the frames.

Cost and simplicity of winter preparations is very important if you have more than a handful of hives. Perfection can be the enemy of practicality.


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## david stern (Dec 13, 2021)

crofter said:


> Perfection can be the enemy of practicality.


Agreed.
This is where I am likely to stumble. I want the perfect hive. I don't have so much umph to experiment at this time, so I keep beating the bushes here on Beesource for guidance- and it's been great so far.

For example, I heard on Beesource that bees didn't predictably use the OTS notch to draw queen cells so, I put it to the test this season and found that to be true. I had used OTS for several years just assuming it worked great.

This looking for perfection is leading to some culling of what doesn't work very well.

The local weather is very significant to me. February in Kansas, before any real bloom happens, it can get warm enough for flight one week and the next it might be -20F for two weeks then back up again.


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## crofter (May 5, 2011)

You can do a lot of experimenting with proof of concept constructions but once confident in them you can simplify. Last winter I had quite elaborate inspection and access wells to view the cluster through the vinyl film and front top entrances that were blocked but could be made available quickly. I am confident enough that I wont find the need to have that function on all hives.

There is one real caveat though with zero top entrance hives, that you must assure bottom entrance does not ice over and cause asphyxiation. Loose snow breathes enough for oxygen/ CO2 exchange. I know that winter stores consumption is lessened but I dont have a comfortable figure for a wintering weight of a double deep colony. 125 lbs gross weight without telescopic cover was my previous target weight with lavish upper ventilation but I can reduce that safely.


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## david stern (Dec 13, 2021)

This winter past was the first time I used the clear poly. The hives had been pretty much overrun with small hive beetles and the traps were not doing much. I found that when I opened the hives I could squash a lot of beetles through the vinyl and did so several times per week. With help from a few of the children, this made a significant impact on the beetles. we are still doing it now and the beetles are mostly under control. I threw the traps away.


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## ursa_minor (Feb 13, 2020)

crofter said:


> You can do a lot of experimenting with proof of concept constructions but once confident in them you can simplify. Last winter I had quite elaborate inspection and access wells to view the cluster through the vinyl film and front top entrances that were blocked but could be made available quickly. I am confident enough that I wont find the need to have that function on all hives.


So can I ask what will be your set up without the access wells?. I had them last year and they worked well and I am considering just using clear poly directly over the frames. My conundrum is that I don't know how to make that accessible to MC sugar feed.


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## crofter (May 5, 2011)

The way I made access possible through the vinyl is to make an opening approx 9 inches square (just grabbing a figure, could be larger or rectangular) then cut another piece about an inch larger in all dimensions to put down either under or over the opening in the main covering sheet: I put it under and attached a gorilla tape pull tab so I could have hauled it up through the opening. If placed above it would be easier to lift. I then made a wooden square rim about 12 inches across as a well to keep hold back the shavings. The well surrounding the access hole was insulated separately with assorted foam scraps and or rags etc. I only had to pull this out to access the vinyl film to see what was going on with the bees. I did not find it necessary to feed.

There are photos of the setup on another thread from last autumn. Without the plastic film to contain the bees below it, the bees cluster on the nice warm ceiling of a quilt box etc. and if you lift it off you expose bees and it is hard to replace without squishing bees. I have always had more than enough stores on the bees but capped sugar syrup does not stimulate them to serious brooding as early as pollen patties would. I probably sacrifice some honey potential but then have not had much swarm preps either.
Easy access without having to deal with loose bees and a difficult to replace upper insulation IS an issue. The well is a workaround. The sonopanel bottoms I used were not fastened to the medium deep box that constitutues top and upper insulation. I will re use them but will fasten to the insulation box. The sonopan (homasote) board kind of delaminates and sheds material where it sticks onto the upper brood box. May skin it with a perimeter of thin wood strips or strips of bubble wrap as a separation plane.

That composition board does wick out some moisture without the loss of warm air. I dont know how enabling that is to the whole concept but would not be too hard to do a comparison with some colonies where a non absorbent ply or strandboard sheet was used. Solid foamboard could be used too if a person did not want to avail themselves of the insulating properties of wood shavings in spare honey super boxes.

I am presently open feeding some frames of capped and half crystallized sugar syrup that did not get used last winter. With the equivalent of approx R20 top insulation and no upper ventilation, winter food consumption is considerably lower. I am not much inclined to see how low I can go, but it would be an interesting experiment.


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## Litsinger (Jun 14, 2018)

A couple of good (and potentially contradictory) articles on this subject in the most recent Bee Culture (attached).

What seems relatively uncontroversial is that all things equal, a lower cluster metabolic rate is better provided that:

1. Liquid does not condense directly above the cluster and;
2. There is enough opportunity for solar gain to support periodic cleansing flights.


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## crofter (May 5, 2011)

Litsinger said:


> A couple of good (and potentially contradictory) articles on this subject in the most recent Bee Culture (attached).
> 
> What seems relatively uncontroversial is that all things equal, a lower cluster metabolic rate is better provided that:
> 
> ...


#1 I have not seen that disputed.
#2 With the discrepancy in climate conditions where bees are kept, this would be next to impossible to define; I think solar gain in many areas would be so commonly a negative influence, that trying to get a controlled net benefit from it would be a complex issue.

"_Relatively uncontroversial_" and "_all things equal_"? Surely you are not talking about beekeeping!😊

If the humidity levels that Mitchel sees as being affective on varroa reproduction success falls within the range that bees attempt to regulate for, I would bet that conditions we can provide would pay dividends. Etienne Tardif's research shows that they do actively regulate relative humidity. Is this range within what Mitchel proposes to affect varroa breeding success? 

If they do not overlap and must be continuously tweaked it may not be practical.


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## GregB (Dec 26, 2017)

crofter said:


> I think solar gain in many areas would be so commonly a negative influence, that trying to get a controlled net benefit from it would be a complex issue.


This popular "solar gain" idea maybe good for the southerly locations but is rather poor for the north with long, snowy winter.
But many a local folk also get confused by the "solar gain" talks.

Flying outside while everything is covered in snow only kills bees.
Wintering in a "fridge", half-asleep is a better idea for us up here.

I personally hate seeing this on a warm and sunny March afternoon - they better be staying put, cause the snow is still cold:


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## crofter (May 5, 2011)

Many of the color schemes put forth to harness solar gain in the few hours it is available, result in greater radiated heat loss in the longer hours without sun; a net energy loss. One enabling theory is that it warms the cluster enabling it to move camp onto adjacent food. There are far more tales of colonies perishing when the cluster drifted to the warmer western side of the hive and left behind empty comb that they could not recross to on the other side of the box. 

Temperature is only one of the conditions necessary to survive. Suitable humidity is essential. Water sources in the frigid dry north is either from the metabolism of honey or snowballs! If the bees have to work too hard to maintain warmth they consume excess stores and produce more water than they need. A cold ceiling is a bad place for it to collect. Indiscriminate placement of insulation is not the simple answer. 

Very large clusters of bees in highly insulated and minimally ventilated hives can create a problem that would not be encountered by Carniolan leaning bees that generally prepare for winter with a smaller cluster. The large volume colony might well do better with a bit more ventilation and less insulation.

Greg has linked to a lot of video depicting consolidating the cluster onto about 6 or 7 frames. With the bees I have which are quite strong to Carniolan traits, they seem to do that themselves. You can feed them more and they will pack it in but dont seem to make the winter cluster bigger.

I dont think there is any one best way to winter when you try to accommodate conditions from the deep south US to the prairies of Can. and bees from Carni to Italian and hives from single deep to triple deep. That keeps things interesting!


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## Litsinger (Jun 14, 2018)

crofter said:


> I think solar gain in many areas would be so commonly a negative influence, that trying to get a controlled net benefit from it would be a complex issue.





GregB said:


> Wintering in a "fridge", half-asleep is a better idea for us up here.


Gents:

I wasn't trying to put too fine a point on it- just comparing the two seemingly disparate articles published in this month's Bee Culture and trying to see what general principles they agreed on.

There is no doubt that there are a lot of factors that go in to overwintering successfully, and these factors may differ even in the same environment with different genetics. 

Both authors are located in the NE, but appear to have different genetics and different priorities when it comes to cluster size and configuration, i.e.:

Carni-type bees- smaller clusters- less need for cleansing flights and vapor control.

Italian-type bees- bigger clusters- more need for cleansing flights and vapor control.

So as usual with bees, it appears the right answer is 'it depends'.


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## A Novice (Sep 15, 2019)

crofter said:


> Many of the color schemes put forth to harness solar gain in the few hours it is available, result in greater radiated heat loss in the longer hours without sun; a net energy loss. One enabling theory is that it warms the cluster enabling it to move camp onto adjacent food. There are far more tales of colonies perishing when the cluster drifted to the warmer western side of the hive and left behind empty comb that they could not recross to on the other side of the box.
> 
> Temperature is only one of the conditions necessary to survive. Suitable humidity is essential. Water sources in the frigid dry north is either from the metabolism of honey or snowballs! If the bees have to work too hard to maintain warmth they consume excess stores and produce more water than they need. A cold ceiling is a bad place for it to collect. Indiscriminate placement of insulation is not the simple answer.
> 
> ...


Agreed.

White painted boxes lose heat just as efficiently as black ones, but don't absorb visible light. That is why white painted things are generally cooler. If you want solar gain, your best bet is a metallic surface, like aluminum foil or chrome.

Ian Steppler up in Manitoba winters indoors at (I think) 40F controlled temperature, in the dark. Winters on 6 frames with good success. As soon as it warms up to where he can't keep the warehouse cool enough, he gets the bees out quick and starts feeding. No cleansing flights for those bees, and winter is long...


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## A Novice (Sep 15, 2019)

While the original article highlights the potential benefits of higher humidity to control Varroa, it seems unlikely that this benefit can be realized at all while wintering bees.

The reason for this is that the benefit appears to occur at absolute water vapor pressures of 4.3kPa or higher. Quoting from the article-

"V_arroa destructor_, a parasite implicated in the spread of pathogenic viruses and colony collapse, ... loses fecundity at absolute humidities of 4.3 kPa (approx. 30 gm−3) "

It isn't realistic to expect to attain that amount of water vapor pressure in the hive in winter, because air won't hold that much water below 30C (86F), and I doubt that it is realistic to maintain an internal hive temperature that high. Inside of the center of the cluster it will be higher than that but falls off pretty rapidly within the cluster.

In the chart below, the vapor pressure P is the maximum partial pressure of water at that temperature. It represents 100% relative humidity. So a relative humidity of 50% at 40C is 
3.69 kPa (50% of 7.38).
At a temperature of about 27C, the same 3.69 kPa corresponds to 100% relative humidity, and so on.












I read the original article that started this discussion. I find some of the suppositional truths about tree hives, etc. to be somewhat questionable. However, if higher humidity is bad for mites, andif higher humidity isn't bad for bees, then designing hives to tend toward higher humidity might improve varroa resistance among honey bees, especially in warm weather.


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## William Bagwell (Sep 4, 2019)

Litsinger said:


> Both authors are located in the NE, but appear to have different genetics and different priorities when it comes to cluster size and configuration, i.e.:
> 
> Carni-type bees- smaller clusters- less need for cleansing flights and vapor control.
> 
> Italian-type bees- bigger clusters- more need for cleansing flights and vapor control.


Seems to agree with the general rule that smaller hives benefit more from insulation than larger hives. Disappointed neither article touched on another general rule I believe in, always have more insulation on the top than the sides. 



Litsinger said:


> So as usual with bees, it appears the right answer is 'it depends'.


Diaper joke in there somewhere, if we could just find it


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## GregB (Dec 26, 2017)

Litsinger said:


> Carni-type bees- smaller clusters- less need for cleansing flights and vapor control.
> 
> Italian-type bees- bigger clusters- more need for cleansing flights and vapor control.


And therein there are differences in hobby vs. commercial approaches/priorities.

The Italian-type bees fit better the commercial priorities whereas the Carni-type bees fit better the hobby types. 
Then along come differing equipment/management styles.

This much must be made clear - very *generally *speaking.
Again - must be written into the ABCs.


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## A Novice (Sep 15, 2019)

A Novice said:


> While the original article highlights the potential benefits of higher humidity to control Varroa, it seems unlikely that this benefit can be realized at all while wintering bees.
> 
> The reason for this is that the benefit appears to occur at absolute water vapor pressures of 4.3kPa or higher. Quoting from the article-
> 
> ...


After I gave it some thought, I concluded that it was probably necessary to keep the relative humidity below 60%, as above that value honey absorbs water from the atmosphere. (this number varies with honey moisture content but is close enough.)

That means the temperature would need to be about 104F (40C), since 0.6 x 7.38 = 4.4.

So my conclusion is the original article is not of practical value, as it is seldom the inside of the hive is that hot, and that is usually when drying honey, and the relative humidity is somewhat lower than 60%.

Even if the honey supers are that hot, the brood nest will probably be about 93F or a little bit warmer.

So don't imagine that a condensing hive resists varroa. It simply won't work.

I wish it would work, but it won't. Math is cruel that way.


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## William Bagwell (Sep 4, 2019)

A Novice said:


> That means the temperature would need to be about 104F (40C)


Interesting as that is just one degree (F) below a thermal treatment. Recent discussion on the MMK forum about how important humidity is for a successful treatment. Not a concern for most locations but is for extremely dry climates such as where a well know bee scientist lives.


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## Litsinger (Jun 14, 2018)

A Novice said:


> Even if the honey supers are that hot, the brood nest will probably be about 93F or a little bit warmer.





Litsinger said:


> At about the 21 minute mark of the following podcast, Dr. Mitchell discusses this concept.


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## Litsinger (Jun 14, 2018)

A Novice said:


> So my conclusion is the original article is not of practical value, as it is seldom the inside of the hive is that hot, and that is usually when drying honey, and the relative humidity is somewhat lower than 60%.


So just as a proof of concept, I plotted the relative humidity value recorded directly above the broodnest from a colony in my yard for the past year (attached).

A few random observations:

1. In the face of such incredibly wide atmospheric changes in relative humidity, bees are masters at controlling their interior environment.

2. Based on these data it appears that the full-year average RH is a bit north of 65%.

3. The highest RH was on December 11 (84.5%) and the lowest RH was on April 20 (59.4%) - both occurred when the ambient RH was near 60% - makes me wonder if they go into economizer mode when they sense that the outdoor RH is near to what they want to maintain.


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## Gray Goose (Sep 4, 2018)

Litsinger said:


> A couple of good (and potentially contradictory) articles on this subject in the most recent Bee Culture (attached).
> 
> What seems relatively uncontroversial is that all things equal, a lower cluster metabolic rate is better provided that:
> 
> ...


well I rarely have the 2.
november till late march.
1 can be worked with.

you likely have both there.

GG


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## joebeewhisperer (May 13, 2020)

clong said:


> Derek Mitchell has another research article that addresses hive configuration and its impacts on humidity. Apparently, it also covers the implications of higher humidity on varroa reproduction.
> 
> Nectar, humidity, honey bees (Apis mellifera) and varroa in summer: a theoretical thermofluid analysis of the fate of water vapour from honey ripening and its implications on the control of Varroa destructor | Journal of The Royal Society Interface
> 
> ...


Thanks for posting! 😃

A friend of mine referenced this but couldn’t remember where he had seen it. I’ll give it a serious read when I’m back on my laptop.
🐝😃


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## A Novice (Sep 15, 2019)

William Bagwell said:


> Interesting as that is just one degree (F) below a thermal treatment. Recent discussion on the MMK forum about how important humidity is for a successful treatment. Not a concern for most locations but is for extremely dry climates such as where a well know bee scientist lives.


Yes. And it shows the utter futility of higher humidity as a check on varroa during wintering.


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## A Novice (Sep 15, 2019)

Litsinger said:


> So just as a proof of concept, I plotted the relative humidity value recorded directly above the broodnest from a colony in my yard for the past year (attached).
> 
> A few random observations:
> 
> ...


True enough.

However, unless the temperature is above 86F, even at 100% RH, there isn't enough water in the air to be effective and inhibiting varroa from reproducing, unless I am misreading the original article.

Since that sort of temperature is not likely in a hive in winter, while wintering at higher humidity may provide benefits controlling varroa isn't one of them.

It is true that inside of the cluster where early brood rearing starts the bees control the atmosphere locally. It is possible that they could be induced to maintain a humidity and temperature inside of the cluster that would be effective against varroa. Since the temperature will be about 93F, all that is needed is very high humidity 81% RH or more. Higher humidity in the cluster should correlate with more food being metabolized, which would correlate with colder air outside of the cluster requiring more heat generation inside of the cluster and thus more fuel consumed. At the same time, good ventilation would remove more moisture peripherally, requiring more moisture generated in the cluster to maintain adequate hydration. So a traditional uninsulated hive with a bottom and top entrance would be the most effective at controlling varroa, whatever its other wintering effects might be.

I do suppose the size of the cluster and the tendency of the bees to brood up inside of the cluster would also be significant variables.

All of that is speculative, but the idea that a warm condensing winter hive is effective against varroa seems unlikely.

I would easily be persuaded I am in error by actual measurements of temperature and humidity from inside of the brood area of a real wintering hive that showed I was wrong. Actual data is the only cure for armchair science.


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## crofter (May 5, 2011)

Unless it is warm enough that there is active brood rearing there will be no place for varroa to breed in regardless of relative humidity. It seemed like a good news story but appears not to mesh with reality.


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## Litsinger (Jun 14, 2018)

A Novice said:


> All of that is speculative, but the idea that a warm condensing winter hive is effective against varroa seems unlikely.





crofter said:


> Unless it is warm enough that there is active brood rearing there will be no place for varroa to breed in regardless of relative humidity.


I could have missed it, but I don't think the intent of the article in question seeks to address overwintering, but rather looks at the active season, specifically when nectar curing is ongoing.


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## crofter (May 5, 2011)

Being that the temperature where the honey is being cured can be higher and the humidity higher than the core of the brood nest, it would not be a problem for the bees in the brood area to achieve the humidity approaching varroa affective if they wished. That is providing we do not open vent the top.
The effects of sacbrood kept my populations down till well on into summer; no problems with bearding  so I was not tempted to allow any top venting.

There are elements of top ventilation for condensation control and drying down of honey that certainly are not intuitive! Small wonder it is controversial.


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## A Novice (Sep 15, 2019)

Litsinger said:


> I could have missed it, but I don't think the intent of the article in question seeks to address overwintering, but rather looks at the active season, specifically when nectar curing is ongoing.


You are right. At the time I indulged my killjoy instinct, the thread had gotten onto the topic of wintering, because humidity and wintering go together in many people's minds. Just pointing out high humidity to keep varroa in check is not a winter phenomenon, thus not an advantage of a condensing winter hive.

In the summer it might have some merit, though it looks to me like a brood nest that hot and that wet would be hard to achieve. 

I read the article rather quickly, and one thing I didn't see was the effect of bees bringing water into the hive to cool the brood nest. This is a common phenomenon. I also didn't see an energy balance on the heat generated by bee metabolism, though I could have missed it.

The premise is that if you do everything you can to make the hive hotter (minimize entrance, add insulation) that the hive will also be wetter, and that this will be effective against Varroa. The idea that the "low humidity hive" is a stressor for bees seems a stretch to me. It seems more likely that the high temperature hive may be more of a stressor.

The question is, if you have a commercial size hive, (or even a warre or some other small format) with no ventilation and lots of insulation, will it be a tolerable hive for bees? Will it get so hot on a hot day that the combs collapse?

Is having water running down the inside of the hive good for bees or woodenware? I have seen those conditions only during the spring buildup. It leads to lots of mold on the inside of the hive, woodenware that wants to warp very badly, etc. Ambient temperatures were pretty low at the time, so not much chance of inhibiting varroa.

None of us know if such hives would be tolerable for bees or bad for varroa. Since Varroa is a new phenomenon, which affects bees in trees and in hives, a hive environment so humid Varroa can't reproduce may be very bad for bees (or not).

The size of the colony, the weather, and the flow all have a huge effect on the humidity of the brood nest. So does the time of day, solar load, etc. Is the reduction in "fecundity" a transient phenomenon, or does it linger for hours or days after exposure to high water vapor pressure? If it is transient, it means probably mites can only get it on from 3 am to 9 am, or if it is cloudy or raining - or something like that. If it is necessary to sustain high humidity for days or weeks, it seems unlikely this apprach would provide any measurable benefit in an actual hive. Remember, mites only do "it" once anyway. If they have to wait a few hours until things are dryer it may not make any difference.

If some intrepid beekeeper wants to try this - seal the hive airtight, maybe with a poly bag or shrink wrap on the outside, with just a small bottom entrance - do it on several hives - I am all for it. Also add an inch or two of insulation. I suspect such hive would get so wet inside it would rot, and by midsummer would be so hot that the combs in the top would collapse. However I could be entirely wrong. 

If the hive produced well and was immune to varroa it would be a nice to have. Varroa is manageable in my opinion, so I wouldn't give up much to get immunity to varroa.

If anyone wants to try this, please keep us posted on your hive design and your results. Bees can survive almost any torture beekeepers subject them to. Maybe mites aren't as tough.


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## Litsinger (Jun 14, 2018)

A Novice said:


> It seems more likely that the high temperature hive may be more of a stressor.


My take-away from Mr. Mitchell's studies and my own observations is that the honey bee colony is a master at maintaining their interior environment, and they utilize all the tools they have at their disposal to maintain their broodnest in a fairly tight temperature and humidity range- particularly when active brood rearing is ongoing (i.e. 92 - 98 degrees F / 65 - 75% RH).

In this regard, the colony is not simply being driven along by the whims of mother nature and the beekeeper but is rather responding to the conditions imposed upon them and taking the necessary steps in an attempt to maintain their preferred environmental parameters.

To this end, the honey bee nest is analogous to our home insofar that we take steps to maintain our environment, both through active means (i.e. air conditioning) or passive means (added insulation).

In this regard, a better thermal envelope is a net benefit, regardless if we are talking about a relatively cold or relatively warm environment:



Litsinger said:


> Derek Mitchell often refers to this study from Saudi Arabia where they found that, _'The heat stress on the honey bees was higher in the normal beehives than in the modified beehives. One might expect the honey bee workers in normal beehives to waste more energy performing effective thermoregulation than those in the modified beehives.'_
> 
> https://www.researchgate.net/public...erformance_Enhance_By_Newly_Modified_Beehives


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## GregB (Dec 26, 2017)

I know @Litsinger, you are only a messenger.


Speaking of:



> Derek Mitchell often refers to this study from Saudi Arabia where they found that, _'The heat stress on the honey bees was higher in the *normal beehives* than in the *modified beehives*. One might expect the honey bee workers in normal beehives to waste more energy performing effective thermoregulation than those in the modified beehives.'_


It should be common sense to most anyone that the human dwellings around the globe are very much *adapted *to the local conditions - as they *should be.*

So this conclusion that a common commercial "normal" box (more or less suitable for certain conditions, but only!) - not working too well in Saudi Arabia - is kind of like realizing the obvious (whoever realized this). 

Appropriate customization of the *conditioned *dwellings - really is a basic common sense with extensive historic support to show the same.

Thermoregulation in general is resource-expensive and must be optimized per the location (and the associated climatic conditions).

Both human and bees' dwellings qualify for the appropriate customization because they are thermoregulated.

So the entire idea of using the same standard commercial (cheap too!) box from Alaska to Saudi Arabia and with good results is patently a poor idea.

Nothing is revolutionary in this realization.


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## Litsinger (Jun 14, 2018)

GregB said:


> So the entire idea of using the same standard commercial box from Alaska to Saudi Arabia and with good results is patently a poor idea.


I think I understand where you're coming from, Greg and you make good points about cavities that are appropriate to the local environment.

The question at-hand however is whether insulation is universally a good idea when it comes to bee nesting cavities- and I believe that Mr. Mitchell would argue it is- both in heating and cooling-dominated climates. This I expect is the 'revolutionary' aspect of his research.


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## GregB (Dec 26, 2017)

Litsinger said:


> I think I understand where you're coming from, Greg and you make good points about cavities that are appropriate to the local environment.
> 
> The question at-hand however is whether insulation is universally a good idea when it comes to bee nesting cavities- and I believe that Mr. Mitchell would argue it is- both in heating and cooling-dominated climates. T*his I expect is the 'revolutionary' aspect of his research.*


I still don't know of the research being revolutionary, Russ.

Here - had Derek M. been not a resident of British Islands but rather Eastern Siberia or Finland - he would have known the same (the need for insulation!) rather customarily thru his daily life.

This realization of his is mostly applicable to himself.

Beekeepers in more hostile environments have known the same all along. They just did not bother publishing anything - because it was routine knowledge to them.

However!
Importantly - there are many cases where excessive insulation is, indeed, NOT needed.
It is nothing but hindrance and excessive weight and bulk.

Caucasian and Balkan beekeepers for hundreds (if not thousands) of years - successfully kept their bees in simple woven baskets, covered with dung and clay. They did it because they could get away with this method in their moderate local conditions (with good results)!

And so - back to "location, location, location".
Rather then "insulation, insulation, insulation"


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## Litsinger (Jun 14, 2018)

GregB said:


> And so - back to "location, location, location".
> Rather then "insulation, insulation, insulation"


No argument from me, Greg. Whether revelatory or not, his assertion that bees (and by extension beekeepers) in the Balkans and indeed in my own relatively mild Mid-South climate would benefit from additional insulation for summer operations (let alone in Saudi Arabia) is not an idea I heard commonly bantered about in contemporary beekeeping literature until Mr. Mitchell postulated it.


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## A Novice (Sep 15, 2019)

I have to admit to being a skeptic related to most published articles.

In grad school I actually had a class in deconstructing journal articles - mostly in Engineering journals, primarily having to do with power electronics and motion control theory.

To put it bluntly, about 80% were pure bunk. They hid the fact they hadn't really done anything useful behind obscure nomenclature and complex partial differential equations.

However, digging down to the details to find out if there was a nugget of actual research or original thought was a lot of work. They made it as difficult as possible so that the peer reviewers wouldn't be willing to actually do the work to understand what they were actually doing. It is relatively hard to write content-free papers in Engineering. In other disciplines there is the added opportunity provided by sample size, confounding of variables, and statistical gimmicry.

This is the game of academic publishing. Publishing is necessary if you are an academic.

So while I can figure out these articles, I hesitate to spend the several hours necessary to get a reasonable assessment of what if anything they have actually determined. I also assume that they are most likely bunk.

One immediate red flag is if the published article is verbose. Prolixity is one of the easiest ways to punish anyone trying to figure out an article, You have to read through all that pointless prose, mostly background and re-stating things already known, and it is a lot of work to do that. This is a favorite method of dressing up nothing to get it published.

Some verifiable statements I will assume are true, like r*eproduction of Varroa is inhibited at absolute water vapor pressures of 4.3 kPa or more*. What I don't know is if this inhibition is transitory and how much latency is associated with it. If Varroa can reproduce normally 5 minutes after the absolute humidity drops to 4.2 kPa, then this effect is likely irrelevant. If reproduction is inhibited for 20 hours or so after absolute humidity drops to 4.2 kPa, then this effect may be of some relevance. However, if it is necessary to maintain absolute humidity at 4.3 kPa continuously for a long period of time in order to beneficially reduce Varroa, I think it is very unlikely that this method of combatting varroa has any potential benefit, as you will be fighting the bees to do it, and the bees will win most likely. 

Looking at Fig. 2 in the article, the normalized fanning response begins increasing at 3 kPa, and goes up linearly. Simply put, bees seem to like a humidity of 3, and the higher you get above that, the harder they fight to bring it back to 3. Fanning appears to be bimodal - essentially zero fanning up to just under 3kPa, and then linearly increasing fanning with increasing humidity as the urge to lower humidity to the optimal value of 3 kPa becomes more compelling. From that figure it is apparent that bees like a humidity of 3 kPa, and will try to get the hive to that value. So trying to hold a humidity of 4.3 is fighting the bees, that want a humidity of 3 kPa.

Looking superficially at the model used to compare tree hives with box hives, I note immediately that the effect of solar loading is not included. This appears to me to be a serious flaw, likely fatal to what follows.

Any heat balance that neglects direct sunlight is incorrect, as solar loading is not insignificant. This is also a major difference between tree hives and box hives. Tree hives are in the shade. It is no defense to say the variables associated with direct solar loading would make the model unwieldy. If the truth is too complicated for your analysis, then you need to admit that, and try a different approach. This would blow up the steady state model assumption (which would be good).

While tree hives are the "natural" habitat, there is no reason to think tree hives, or hives that approximate tree hives in their thermal or humidity related performance are better in any way than other hives that do not. That tree hives have different characteristics than box hives is readily apparent. That tree hives are better in any way than box hives is not apparent. This is especially true of resistance to Varroa, a late introduced parasite.

My brother Brian works with tribal people in eastern India. These people live in "natural" houses - as tribal people do all over the world. Their houses have no insulation, often no doors, floors, or source of heat or cooling. without sinks, tubs, washcloths or hand or body soap, they wash a good deal less, and less effectively, than is customary in western cultures. They get their water from a stream, which they and their neighbors up and downstream use to carry away waste. They defecate in the open outside. they have no toilet paper. They cook their food outside. He sent me a list of the people living in one village - of 160 people not one was over the age of 60.
Natural isn't better - it is what is available. These people would easily adapt to living as we do, and their health would improve significantly. However, what is available to them works. It is like a bee colony in a tree.

Bees live in trees, not because trees are better than boxes, but because trees are better than hanging combs from a branch. People live in caves because it is better than being rained on. Never mind the bats.

The article does raise some interesting questions, as I doubt anyone has investigated the benefits of ventilation during the summer months at the extremely low levels of ventilation postulated for tree hives.

Reverse engineering their charts, it looks like a similar thermal performance could be achieved by having 5 inch thick wood walls, or 1.5 inches of EPS foam. In their model, no moisture escapes through the walls - they are airtight. Moisture only escapes through the entrance by fanning, or as liquid dripping down the inside.

Since their model is steady state, the wood surrounding the colony is saturated with water, and no water goes in or out. This can most easily be simulated by an impermeable layer on the inside of the nest walls. (I think this is a horribly bad assumption on their part, but it is what it is)

Simulating their equivalent entrance size is somewhat more complex, since tree hives are assumed to be smaller than box hives, and the appropriate entrance size should scale with the number of bees in the hive I would think.

However, there is a good deal of overlap, and an entrance size of 1/2 inch by 3 inch would seem appropriate.

So if someone wants to try this, the easiest way would be to place a layer of polyethylene around a conventional wooden hive - I recommend 6 mil minimum, as it is far less susceptible to holes and leaks than the thin stuff.
Place the polyethylene sheet over the inner cover and the outside of the hive, draped down the sides so nothing can get out. Place a similar layer of poly across the bottom of the hive, leaving a few holes for water to run out. This can be on the inside of the bottom board.

Over the poly, place a tightly fitted EPS box. 1.25 inches is ideal, but 1.5 inches is OK. Glue the box together continuously along all edges with gorilla glue. (tape the seams until the glue sets). Place a 1.5-inch layer of EPS foam on the bottom below the clear poly, possibly below the bottom board.

Provide an entrance through the tightly fitted EPS foam of the sides and bottom of about 0.5 inches by 3 inches.

That should do it. Having wood inside of the vapor barrier is a departure from the model in the paper, but I think it won't make much difference.

I would put the hive in the shade...

If someone wants to try this hive, and see if it resists varroa, I would be very interested in what you discover. 

Ideally, run about 10 hives like this, and 10 as conventional hives. Compare them on reasonable metrics:

Mite counts at intervals.
Colony survival.
Honey production.

I would be willing to bet a cheeseburger that the bees will do worse in the insulated hive, as they will need to limit brood rearing and nectar gathering in order to keep humidity in bounds. I also suspect the inside of the insulated hive will rot due to excessive humidity and resulting fungal growth. This is your chance to prove me wrong!

Sorry for the length of this rant.

Jon


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## GregB (Dec 26, 2017)

A Novice said:


> Natural isn't better - it is what is available.


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## GregB (Dec 26, 2017)

A Novice said:


> I also suspect the inside of the insulated hive will rot due to excessive humidity and resulting fungal growth.


Absolutely will rot.
Just as the natural tree hives rot - that is what they do all along, they naturally rot.


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## Litsinger (Jun 14, 2018)

A Novice said:


> I would be willing to bet a cheeseburger that the bees will do worse in the insulated hive, as they will need to limit brood rearing and nectar gathering in order to keep humidity in bounds. I also suspect the inside of the insulated hive will rot due to excessive humidity and resulting fungal growth.


Good write-up, Jon. Let's just make sure we are all on the same page. We'll assume for the sake of argument that a 4.3 kPa vapor pressure is the 'magic number' we need to hit in order to significantly forestall varroa growth. If we compare this to a reasonable range of internal temperatures, it equates to the following approximate relative humidities:

92 F = 84% RH
95 F = 76% RH
98 F = 70% RH

So while the relative humidity we are looking for is elevated versus what I have typically recorded onsite, it is certainly within easy reach of what can be achieved (at least in my climate) without the risk of suffocating the bees or having it rain inside the cavity.

The second fundamental is that of whether insulation is a net benefit during the active season- the paper from Saudi Arabia (referenced above) published the following data, which shows that the non-insulated cavity performed worst against the alternatives at temperatures of literally over 100 degrees in the shade. And not only this, the insulated colonies performed better than the non-insulated colonies in almost every observed metric but pollen storage:










And finally, I am trying to wrap my mind around how a non-insulated assembly would be expected to perform better in a direct solar gain environment than a similarly emissive insulated assembly?

What I take away from the Saudi study, Mr. Mitchell's evaluations and my own humble observations is that all things equal a colony will prioritize maintaining the sensible nest temperature even if it means letting the overall humidity level rise. So whether an elevated humidity is a net benefit to the colony I would say is less than certain, but it does appear that a more thermally-resistant envelope is generally a net benefit to colonies in a wide range of climates.

Interesting discussion- it's a facinating concept to consider.


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## A Novice (Sep 15, 2019)

Litsinger said:


> Good write-up, Jon. Let's just make sure we are all on the same page. We'll assume for the sake of argument that a 4.3 kPa vapor pressure is the 'magic number' we need to hit in order to significantly forestall varroa growth. If we compare this to a reasonable range of internal temperatures, it equates to the following approximate relative humidities:
> 
> 92 F = 84% RH
> 95 F = 76% RH
> ...


Good points. It looks to me like it will be hard to get to those levels of absolute humidity, as the bees seem to prefer 3 kPa or lower. My "test" hive is just an attempt to create a hive that matches the model hive from the analysis. I don't think I will try it any time soon.



Litsinger said:


> The second fundamental is that of whether insulation is a net benefit during the active season- the paper from Saudi Arabia (referenced above) published the following data, which shows that the non-insulated cavity performed worst against the alternatives at temperatures of literally over 100 degrees in the shade. And not only this, the insulated colonies performed better than the non-insulated colonies in almost every observed metric but pollen storage:
> 
> View attachment 71057


The Saudi study makes sense. If the outside temperature is higher than the inside temperature flow of heat is inward. Reducing the inward flow helps reduce the amount of cooling the bees need to provide.
Even in Wisconsin hives are too hot, the bees are fanning and bearding. However since the outside temperature is lower than the inside hive temperature the heat flow through the walls is outward, and so less insulation means the bees don't have to work as hard to cool the hive. In that case insulation would add to the stress on the bees.


Litsinger said:


> And finally, I am trying to wrap my mind around how a non-insulated assembly would be expected to perform better in a direct solar gain environment than a similarly emissive insulated assembly?


I remember back in '79, Dr Sparrow related that he had almost gotten fired his first job out of school for calculating the temperature expected from a pole mounted transformer as being lower than ambient air temperature. He was correct, of course. He also related somewhat earlier that he was the greatest living authority on the subject of heat transfer. That was just a fact, and he wasn't boasting.
Heat transfer, especially involving radiant heat transfer, is not intuitive to most people.

So let's begin by considering the outside temperature of a bright white object exposed to sunlight and surrounded by objects at various temperatures. 
A bright white object at normal ambient temperatures has an emissivity of very nearly 1 at its "color temperature", the temperature it is radiating at. Its color temperature is its actual temperature, and all of the light it emits is in the infrared part of the spectrum.
Radiant heat transfer will be exchanged between the object and the sky, which is at a color temperature of about -40C. 
It will lose heat to the sky because the sky is so cold. 
This is why a pole transformer is relatively cool, because it is up in the air, and mostly it sees the sky, which is very cold.
Radiant heat transfer will be exchanged between the object and the terrestrial objects around it which are at roughly ambient air temperature.
Since the temperature of ambient objects and their emissivity is similar to the bright white object, not much heat is exchanged.
Overall, heat will be lost to the sky, and the object temperature will be slightly to significantly lower than the ambient temperature.
Since a bright white object has an emissivity of roughly zero in the near infrared and visible part of the spectrum, at the color temperature of light coming from the sun, the amount of heat gained from the sun will be relatively small, mostly due to the infrared light included in sunlight.
This is why a white object in direct sunlight can be significantly cooler than ambient temperature. This is something you can easily confirm.
So the outside temperature of the object is at or below the ambient temperature.

If that object is a beehive, it has a colony of bees in it which generate heat and need to lose heat in order to thermoregulate. Since the outside temperature of the beehive is lower than the inside (assuming ambient temperature is lower than the regulated colony temperature) the colony can lose heat by conduction through the hive walls.

In general, the colony can lose heat by conduction through the walls as long as the outside hive surface temperature is lower than the inside hive temperature. The amount of heat it can lose in this way is inversely proportional to the thermal resistance (amount of insulation) and directly proportional to the temperature difference between the inside of the hive and its outside surface. More insulation means less heat flow. 
The outside of a hive painted white is usually pretty cool, even when full of bees.
Insulation slows heat transfer through the hive walls.

That is how it works.

We neglected convection on the outside of the hive, which tends to make the outside temperature closer to ambient air temperature, and a few other things which would be needed in a full heat transfer analysis, but this is close enough I think.

As a side note, Mitchell's model assumes all heat lost from the colony is by conduction through the hive walls, and all moisture is lost as liquid running down the sides.

If your hives are dark brown, the equation shifts a bit. If they are polished chrome, they will be hot in the sun, and everything changes.


Litsinger said:


> What I take away from the Saudi study, Mr. Mitchell's evaluations and my own humble observations is that all things equal a colony will prioritize maintaining the sensible nest temperature even if it means letting the overall humidity level rise. So whether an elevated humidity is a net benefit to the colony I would say is less than certain,


Agreed.


Litsinger said:


> but it does appear that a more thermally-resistant envelope is generally a net benefit to colonies in a wide range of climates.


That is not as clear.
I think a thermally massive envelope (one that holds heat) is likely to be beneficial in most environments, as it reduces the swings in temperature which can be damaging.


Litsinger said:


> Interesting discussion- it's a fascinating concept to consider.


Yes it is. I actually hope somebody takes up my challenge. It is hard to say what would happen.


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## Litsinger (Jun 14, 2018)

A Novice said:


> The Saudi study makes sense. If the outside temperature is higher than the inside temperature flow of heat is inward. Reducing the inward flow helps reduce the amount of cooling the bees need to provide.
> Even in Wisconsin hives are too hot, the bees are fanning and bearding. However since the outside temperature is lower than the inside hive temperature the heat flow through the walls is outward, and so less insulation means the bees don't have to work as hard to cool the hive. In that case insulation would add to the stress on the bees.





A Novice said:


> If that object is a beehive, it has a colony of bees in it which generate heat and need to lose heat in order to thermoregulate. Since the outside temperature of the beehive is lower than the inside (assuming ambient temperature is lower than the regulated colony temperature) the colony can lose heat by conduction through the hive walls.


Jon:

Thank you for the feedback- good stuff. So based on your feedback, are you assuming that:

1. The majority of cooling heat transfer in colonies in temperate climates is by direct convection? I would have assumed it was primarily via adiabatic cooling produced by the desiccation of nectar and/or the introduction of moisture to the colony via water collection and that fanning and bearding would not necessarily be in direct response to the nest being too hot as potentially being too humid for their liking. I think this is the working theory that Mr. Mitchell postulates via Figure 1 below.

2. If the uninsulated and insulated assemblies have a similar emissivity, we could consider the relative radiant heat transfer as negligible when colonies are located in full sun? In other words, it is not predominantly radiant effects that you are suggesting would make an insulated colony hotter than a non-insulated colony in the sun, but rather the lower conductive heat transfer brought about by the more thermally-massive envelope?


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## A Novice (Sep 15, 2019)

Litsinger said:


> Jon:
> 
> Thank you for the feedback- good stuff. So based on your feedback, are you assuming that:
> 
> 1. The majority of cooling heat transfer in colonies in temperate climates is by direct convection?


No.
I am only assuming that some amount of heat is lost through conduction through the hive wall, and subsequent conduction/convection with outside air and structures, and radiation from the outside of the hive. Increasing the insulation will reduce conduction of heat.
Basic heat transfer.
If heat loss through the hive wall is not significant, then insulating the hive wall does not have a significant effect.
Michell's model assumes all heat transfer occurs in this way. Since his is a condensing hive, water only leaves as liquid and comes in as liquid. - negligible net heat transfer.


Litsinger said:


> I would have assumed it was primarily via adiabatic cooling produced by the desiccation of nectar and/or the introduction of moisture to the colony via water collection and that fanning and bearding would not necessarily be in direct response to the nest being too hot as potentially being too humid for their liking. I think this is the working theory that Mr. Mitchell postulates via Figure 1 below.


I don't think that is correct.
The diagram below shows fluid transfers. While there is a loop for "entrance heat advection', it is ignored in his model. (see quote below) You will see that all water enters as liquid and leaves as liquid. As a result, no heat is transferred by water moving through the hive.
As he states (text not *BOLD* in original)

_"In this model, which is a simplification of a complex system: 
— Water vapour enters the system from nectar evaporation, nectar consumption and through entrance inlet airflow by forced convection. 
— Water vapour leaves via condensation and entrance exhaust flow. 
— Heat energy is produced by metabolizing sugars. 
— Heat energy exits via conduction through the nest walls. *The heat flows of the entrance gases are* insignificant in comparison (approx. 10 mW versus approximately 100 W) [8] and *ignored*. 
— The pollen to insect protein process is considered as a constant rate metabolic energy overhead that consumes nectar, releasing water vapour from its water content and oxidation."_

This is understood to be his model for a condensing hive, not for an ordinary box hive. Not sure what that model would look like, but he appears to consider convection through the hive as not significant, at least in this case.


Litsinger said:


> 2. If the uninsulated and insulated assemblies have a similar emissivity, we could consider the relative radiant heat transfer as negligible when colonies are located in full sun? In other words, it is not predominantly radiant effects that you are suggesting would make an insulated colony hotter than a non-insulated colony in the sun, but rather the lower conductive heat transfer brought about by the more thermally-massive envelope?


Approximately.
Insulation typically has negligible thermal mass - it does not store significant amounts heat.
The higher resistance to heat transfer through insulative materials is due to low thermal conductance.
It is this higher resistance to heat transfer which makes the insulated colony hotter.

For an example - a water jacket around a hive would have very high thermal mass, as water has a high specific heat. However, a water jacket would have less insulative power than a similar thickness of wood, because water has a high thermal conductivity.
Water is a particularly bad insulator but has high thermal mass.

Mitchell's model is a steady state model, which means that thermal mass is irrelevant, as everything is at steady state. This is one of several serious limitations of his model.

The original article is typical of academic stuff. When you make the effort to really understand it - which requires a good deal of work and a significant amount of background knowledge - the model is overly simplistic and unrealistic. it may be a somewhat reasonable though limited model of a colony in a tree, but if it demonstrates anything, it is that building a hive that mimics a tree is not very appealing. Building a house that works like an igloo, or a cave, or a stick hut plastered with dung and mud isn't very appealing either.

It isn't that the article is useless. As academic articles go, it is better than most. However, in the academic publishing world, the game is to dress nothing up in charts, plots, diagrams and complex prose so that it looks like something significant. I found the article quite interesting. Mitchell does suggest some avenues of exploration in hive design. If I were young and had a lot of money and nothing else to do, I might pursue them.


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## Litsinger (Jun 14, 2018)

A Novice said:


> If heat loss through the hive wall is not significant, then insulating the hive wall does not have a significant effect.





A Novice said:


> The diagram below shows fluid transfers. While there is a loop for "entrance heat advection', it is ignored in his model. (see quote below) You will see that all water enters as liquid and leaves as liquid. As a result, no heat is transferred by water moving through the hive.


Jon:

First off, my apologies for the delay in reply- it has been CRAZY at work of late. Secondly, I will be the first to admit that while I am an ME by training and work in the building sciences field as a vocation, the mechanisms at work inside a honey bee nest still straddle the line between impossibly difficult to understand and magic in my mind.

That out of the way, I went back and reread Mr. Mitchell's study previous to the one currently under consideration as it was this study that had lead me to the thoughts that higher cavity thermal mass was universally good and that nest temperature and humidity dynamics were dominated by nectar desiccation during the active season. While he might be misguided, here are a few of the takeaways from this study: Thermal efficiency extends distance and variety for honeybee foragers: analysis of the energetics of nectar collection and desiccation by Apis mellifera | Journal of The Royal Society Interface

_'In temperate climates, the nest temperatures are usually significantly higher than ambient. Given the above analysis and observations, one may discount the outside environment as being a major contributor of energy to desiccation, and is instead more likely to be a potential loss. This scenario forms the focus in this analysis.'

'The thermal efficiency of nectar desiccation is dependent on the lumped conductance of the nest, the averaged temperature difference between the inside and outside of the nest, and the rate of water being evaporated…'

'The requirement to retain elevated temperatures, and hence reduced RH where the desiccation is taking place, shows an all year round advantage for nests with low thermal conductance. This would drive honeybees to seek out such nest sites, i.e. tree hollows rather than ground crevices, with lower thermal conductance values (thick wooden walls, bottom entrances) and modify, where possible, nest sites to further reduce the conductance value by, for example, closing up holes with propolis.'

'Desiccation of honey takes a significant percentage of the energy delivered to the hive in the form of nectar for A. mellifera, particularly in the northern part of their range where nectar is lower in concentration. Typical values show that over 50% of the delivered energy may be used in the process of honey ripening and even in exceptionally favourable circumstances for temperate climates, do not use less than 25%.'_

In addition, I went back and reread his original study which considered nest conductance and it's theoretical implications for colony health: 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

A couple observations from this paper:

_'As described above, the humidity in the air surrounding the nest will rise to circa 90% RH _[in low conductance assemblies]_. Regulation to lower humidity can then be achieved by circulation of the air into the parts of the nest where the walls are cooler. In this case, the latent heat released by condensation is contained within the nest. The net energy required is only that necessary to heat air from the required RH and dew point, back to 34° C, which is less than the latent heat released by condensation. High MCR _[ratio of colony mass to lumped enclosure thermal conductance] _enclosures, by reducing the energy expenditure in humidity control and enabling other humidity control mechanisms, may reveal more honeybee humidity control behaviours.'

'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.'_

So my dumb country boy understanding of this is as follows:

1. Highly thermally resistant assemblies are a net benefit to colonies in temperate climates as they minimize skin losses and allow higher temperatures to be maintained during the process of nectar desiccation and thus improve colony honey production efficiency.

2. Increased temperature, lower roof/wall conductance and the corresponding improved nectar processing rates allow for increased cavity relative humidity- which might improve brood viability and reduce varroa reproduction.

Interesting stuff- wonder if there are any folks here on Beesource that have both Wooden and Insulation Sandwiched or Polystyrene colonies who can comment on what they've observed during the active season?


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## GregB (Dec 26, 2017)

Litsinger said:


> Interesting stuff- wonder if there are any folks here on Beesource that have both Wooden and Insulation Sandwiched or Polystyrene colonies who can comment on what they've observed during the active season?


My mini-cooler hives are very moist.
Even with slightly cool nights, those small colonies create water condensation already (in the far corners).

Unsure I need to be concerned or not.

Before any anti-mite benefits are realized, I hope the bees don't die of the excessive water issues over the winter.
Even the most healthy bees can not really survive if wet in our winter.


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## crofter (May 5, 2011)

Would the ratio of opening area to hive volume not be largely different than say a colony in a double deep hive? With so little thermal mass the shell would quickly drop to outside night temps. We have been getting night temperature down to 50 F.


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## Gray Goose (Sep 4, 2018)

A Novice said:


> I would be willing to bet a cheeseburger that the bees will do worse in the insulated hive, as they will need to limit brood rearing and nectar gathering in order to keep humidity in bounds. I also suspect the inside of the insulated hive will rot due to excessive humidity and resulting fungal growth. This is your chance to prove me wrong!


you can bet if you want.
I have 2 hives with 4 inch walls and also from that "good" experience made 7 hives with 3 inch walls.
Maintaining the temp the bees like is easier with the extra insulation in winter and summer.

not sure I will ever write a paper. and yes the walls are damp, at times wet. But these bees are alive and produce more honey that the other single wall hives and make me more splits.

they do not limit brood rearing, contrary it is wall to wall as the "nest" can be expanded rather easy.
As a matter of fact I have problems moving brood from the insulated hive, to a normal comercial hive as it is wall to wall and the cluster in the split often cannot keep it all warm.

armchair science can go both ways, until I read proof insulation does not work, I plan to keep using it.

AND you have not proven your self right yet IMO.

Make a few insulated hives use them for 5 years , then maybe we can talk.

GG


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## A Novice (Sep 15, 2019)

Litsinger said:


> Jon:
> 
> First off, my apologies for the delay in reply- it has been CRAZY at work of late. Secondly, I will be the first to admit that while I am an ME by training and work in the building sciences field as a vocation, the mechanisms at work inside a honey bee nest still straddle the line between impossibly difficult to understand and magic in my mind.
> 
> ...


I have to admit that I don't really understand these articles and am unwilling to make the effort to do so. The relationship between the summary statements and the actual modeling is tenuous at best, so just reading the prose summaries doesn't seem to me to be helpful. At best they suggest experiments one might make.

Your understanding may be correct.

If a summer hive is trying to lose moisture while conserving heat then a condensing hive is beneficial.

My thinking until now is that a summer hive is trying to lose both heat and moisture, while balancing the two.
However, that is just an assumption on my part. Bees generate a lot of heat in my observation.

There seems to be a general trend to conflate thermal mass and insulation, which is surprising to me, since they are very difficult things.


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## A Novice (Sep 15, 2019)

Gray Goose said:


> you can bet if you want.
> I have 2 hives with 4 inch walls and also from that "good" experience made 7 hives with 3 inch walls.
> Maintaining the temp the bees like is easier with the extra insulation in winter and summer.
> 
> ...


OK!

Actual results!

I probably owe you a cheeseburger.

What sort of wall construction? What sort of entrances?

How well sealed are the hives? Do you have pictures?


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## Gray Goose (Sep 4, 2018)

A Novice said:


> OK!
> 
> Actual results!
> 
> ...


second set is a "buckeye look alike, with wool pannels made 7 sets of 4 boxes.





























pannels are 2 deep plus 2 medium, which is my favorite size.

GG


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## Gray Goose (Sep 4, 2018)

first set was a double deep lang frame long hive.
2x4 walls with R13 insulation, 3/4 T&G inside sheathing and 1/2 green ply exterior. 3 inch foam lid insert.
are OD 48 Inch to optimize the Ply which was 4X 8 foot sheets.





































drawers under for debris assessment and air under.
spring pollen patty add, 10 days before dandelion.
and the inside was wet with bees licking water.
best wintering hives , had first drones and were ready for first splits, about 2 weeks before the other single wall hives.
used the plans section of "keeping bees with a smile" then added the full 2x4 wall to the plan.

GG


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## A Novice (Sep 15, 2019)

Gray Goose said:


> first set was a double deep lang frame long hive.
> 2x4 walls with R13 insulation, 3/4 T&G inside sheathing and 1/2 green ply exterior. 3 inch foam lid insert.
> are OD 48 Inch to optimize the Ply which was 4X 8 foot sheets.
> 
> ...


So what sort of entrances do you have? Any ventilation?


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## Gray Goose (Sep 4, 2018)

A Novice said:


> So what sort of entrances do you have? Any ventilation?


on the double wall, 8F lang
5/8 x 13.75 the front of the hive basically.
I use blocks to reduce.

On the long hive a slit 5/8 x 12 or so , partially blocked so 8 ish wide.
no ventilation. well what air gets aroung the drawers is ventilation I guess.

for the deep long I started with plan 27 of the following URL and just used 2x4s for a wall and insulated and sheathed side.





Natural Beekeeping | Horizontal Hives | Do-It-Yourself Plans







horizontalhive.com





I am not thinking upper entrances will be for me.

GG


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## AR1 (Feb 5, 2017)

Gray Goose said:


> first set was a double deep lang frame long hive.
> 2x4 walls with R13 insulation, 3/4 T&G inside sheathing and 1/2 green ply exterior. 3 inch foam lid insert.
> are OD 48 Inch to optimize the Ply which was 4X 8 foot sheets.
> 
> GG


Dangit you guys! Now it looks like I have to go back to page one and read this entire thread! Just popped in to the last page to see what all the fuss and continuing posts were about, and it looks interesting.


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## romaning (4 mo ago)

Gray Goose said:


> and yes the walls are damp, at times wet.


Nice work Gray Goose. I would like to ask about material between wooden walls. Is it wool from sheep (natural wool) or insulation material (for construction)?

Do you have some mould inside of beehive or on combs?

I thing this material is better than XPS (polystyren). It is not to much hermetic close.
Did you see some possitive benefits with bigger insulation? Less varroa....

I would like to try make a reed beehive. Reed has similar insulating properties like XPS.

I am from Central Europe, temperate climates like Mr. Derek Mitchell, so I will try his theory











Litsinger said:


> 92 F = 84% RH
> 95 F = 76% RH
> 98 F = 70% RH


And thank Litsinger for the convert table from kPa to temperature/RH
Now it is more transparent

(Sorry for my bad english )


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## Litsinger (Jun 14, 2018)

romaning said:


> And thank Litsinger for the convert table from kPa to temperature/RH


Glad to help. Sounds like you are asking the right questions, and I am looking forward to reading about your experiments.


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## Gray Goose (Sep 4, 2018)

romaning said:


> I would like to ask about material between wooden walls. Is it wool from sheep (natural wool) or insulation material (for construction)?


in the 2x4 wall I used the pink fiberglass insulation with vapor barrier, just like a wall in a home. (3.5 inch R13)
in the 1.5 inch space of the Buckeye hive, I made 1.5 inch wool (raw) panels



romaning said:


> Do you have some mould inside of beehive or on combs?


not on the combs, only on the insulation panels, the 1.5 inch wool ones, interestingly on the outer of the panel and inner of the outer wall, I presume it is there, where the condensation occurred.



romaning said:


> I would like to try make a reed beehive. Reed has similar insulating properties like XPS.


make one give it a try, always nice to try and learn. they are hollow and have insulative properties, should work.

good luck

GG


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## AR1 (Feb 5, 2017)

Gray Goose said:


> in the 2x4 wall I used the pink fiberglass insulation with vapor barrier, just like a wall in a home. (3.5 inch R13)
> 
> 
> GG


That is exactly what I have used the last 3 years, on the tops though, not the sides. This year in my smaller colonies I plan to keep them in the 10-frame boxes but with the fiberglass on the outside edges too. No problems so far.


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## Gray Goose (Sep 4, 2018)

AR1 said:


> That is exactly what I have used the last 3 years, on the tops though, not the sides. This year in my smaller colonies I plan to keep them in the 10-frame boxes but with the fiberglass on the outside edges too. No problems so far.


AR it is in the wall 2x4 studs, 1/2 green plywood exterior, and 3/4 pine T&G on the inside.
whole thing under a roof.

GG


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## A Novice (Sep 15, 2019)

Gray Goose said:


> on the double wall, 8F lang
> 5/8 x 13.75 the front of the hive basically.
> I use blocks to reduce.
> 
> ...


Finally getting back to this...

So is there any way for moisture to escape from these hives, other than by dripping out the bottom?

The hive in Michell's model only has water escaping by condensing on the walls and dripping down.

My thinking is that water vapor carries away a lot of heat, while liquid water carries away essentially none - water enters hive as liquid and leaves the hive as liquid. it is like 540 cal/g for heat of vaporization, vs 1 cal/g per degree C for warming liquid. Any vapor that leaves the hive carries a lot of heat with it.

If the goal is to keep the hive cool, having vapor exit the hive would be helpful.

However, that is armchair science...


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## Litsinger (Jun 14, 2018)

A Novice said:


> If the goal is to keep the hive cool, having vapor exit the hive would be helpful.


I think Mr. Mitchell is suggesting they are trying to keep the hive warm- and the less energy they have to expend to do so, the better.

His assertion is that in order to desiccate nectar they need a temperature of approximately 40 degrees C (104 degrees F):






Thermal Efficiency | Bee Culture







www.beeculture.com


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## A Novice (Sep 15, 2019)

Litsinger said:


> I think Mr. Mitchell is suggesting they are trying to keep the hive warm- and the less energy they have to expend to do so, the better.
> 
> His assertion is that in order to desiccate nectar they need a temperature of approximately 40 degrees C (104 degrees F):
> 
> ...


In that case, why are bees bearding on my hives whenever the hive gets hot?
Their metabolic load would help keep the hive hot if they went back inside.
Serious question.
Maybe they don't like the low relative humidity...
Perhaps they are outside to prevent heating the hive hotter, which would lower the humidity even lower. (that is possible)
But then why are they fanning at the entrance. That both lowers humidity and temperature.

The bees must be crazy!


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## Litsinger (Jun 14, 2018)

A Novice said:


> But then why are they fanning at the entrance. That both lowers humidity and temperature.


Good questions, Jon. The first big question is whether fanning in-fact seeks to lower humidity and temperature. I expect this is dependent upon several factors, not the least of which is whether they are working to convert liquid water into vapor.

As Mr. Mitchell describes, _They use a similar process _[to boiling on a stovetop]_, evaporation, and it takes a similar amount of energy (slightly larger in fact), as if you tried to do it on your kitchen stove. Anyone who has tried a recipe where it says “add a bottle of wine and reduce by half,” or made jam or marmalade can attest to the amount of gas or electricity and time that takes i.e. a lot of energy. It takes 0.61 kilowatt hours (kWh) to change one kg of liquid water at 100°C into water vapour at 100°C. So it would need 18.3 kWh on the stove to change 30kg of liquid water at 100°C in to vapour. They do not use a stove but lap at it with their tongues for a few minutes, then heat the air gently with their bodies and move that air by fanning their wings for hours to drive off the water content. It takes 0.67kWh per kg to evaporate water at 40°C. That means 20kWh of energy to make 30kg water at 40°C change into vapour. _

And while it is a swag on my part, I have almost concluded that bearding is not necessarily a sign of a nest temperature that is too high, but one that might be too humid for their collective liking. It seems especially pronounced around here during times where there is both nectar inbound and high ambient humidity. But this is speculation on my part.


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## crofter (May 5, 2011)

A Novice said:


> In that case, why are bees bearding on my hives whenever the hive gets hot?
> Their metabolic load would help keep the hive hot if they went back inside.
> Serious question.
> Maybe they don't like the low relative humidity...
> ...


Saw some video recently that showed bees pointed up on one inside hive wall, and down on the opposite. As air in the immediate area of the evaporation process would otherwise become saturated if not moved away, it needs to be circulated; not necessarily removed from the hive, but circulated within. I believe that under some conditions that air velocity trumps temperature. My conjecture is that too many bee bodies interfere with the in hive air circulation; outside bearding allows optimum in hive air movement.

Bees appear to have very effective zone control of both temperature and humidity in the separate brood area and the nectar drying area.
The bees at the bottom entrance could selectively pull off a portion to expel, which would be at an optimum efficiency temp./ R. humidity value.

Stupid bugs!


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## A Novice (Sep 15, 2019)

crofter said:


> Saw some video recently that showed bees pointed up on one inside hive wall, and down on the opposite. As air in the immediate area of the evaporation process would otherwise become saturated if not moved away, it needs to be circulated; not necessarily removed from the hive, but circulated within. I believe that under some conditions that air velocity trumps temperature. My conjecture is that too many bee bodies interfere with the in hive air circulation; outside bearding allows optimum in hive air movement.
> 
> Bees appear to have very effective zone control of both temperature and humidity in the separate brood area and the nectar drying area.
> The bees at the bottom entrance could selectively pull off a portion to expel, which would be at an optimum efficiency temp./ R. humidity value.
> ...


interesting possibility.

It doesn't square with Mitchell's hypotheses, that heat is only removed by conduction through the hive walls, and water is only removed by condensation and dripping out of the hive. But it could be correct.


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## Litsinger (Jun 14, 2018)

A Novice said:


> ... water is only removed by condensation and dripping out of the hive.


I concur with the assessment concerning heat, but moisture appears to be assumed as removed by both condensation and advection (emphasis mine):

_Water vapour enters the system from nectar evaporation, nectar consumption and through entrance inlet air low by forced convection.

Water vapour leaves via condensation and entrance exhaust flow.

Heat energy is produced by metabolising sugars.

Heat energy exits via conduction through the nest walls. The heat flows of the entrance gases are insignificant in comparison (~10mW vs ~100W) and ignored.

The pollen to insect protein processes are considered as a constant rate metabolic energy overhead that consumes nectar, releasing water vapour from its water content and oxidation._


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## Gray Goose (Sep 4, 2018)

A Novice said:


> The hive in Michell's model only has water escaping by condensing on the walls and dripping down.


air flow as in the hive is not sealed, air is coming in and going out.
moisture goes thru wood, as does heat.
bees drink water and release some in flight (non winter)
honey can absorb water
winter brood rearing takes water.
water can be stored in cells on the edge of the hive.

I worry more about them running out of water than it dripping.

GG


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## A Novice (Sep 15, 2019)

Litsinger said:


> I concur with the assessment concerning heat, but moisture appears to be assumed as removed by both condensation and advection (emphasis mine):
> 
> _Water vapour enters the system from nectar evaporation, nectar consumption and through entrance inlet air low by forced convection.
> 
> ...


You are correct. Water is removed only through the entrance by air circulation or by liquid running out.
This means no water leaving through the walls of the hive. Hard to achieve in a dry wood structure without a vapor barrier.


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## crofter (May 5, 2011)

Saying "no water" is an absolute where as the intention may have been that movement by that means was not a major influence. Is that point a "red herring" in regard to the merits of Mitchell's main assumption?


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## Litsinger (Jun 14, 2018)

A Novice said:


> This means no water leaving through the walls of the hive. Hard to achieve in a dry wood structure without a vapor barrier.


I believe he addresses this in his analysis- suggesting it is not significant when compared to the moisture removal rates due to condensation and advection:

_'The permeability of the honeybee applied propolis lining (plant resins) is of the order of 10–13 kg m−1 s−1 Pa−1. This results in a flow rate of the order of 2 mg s−1 at a water vapour pressure differential of 5 kPa and a thickness of 0.25 mm. This is insignificant compared to water removal rates up to 100 mg s−1 for condensation and advection.'_


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## Gray Goose (Sep 4, 2018)

A Novice said:


> You are correct. Water is removed only through the entrance by air circulation or by liquid running out.
> This means* no water leaving through the walls of the hive*. Hard to achieve in a dry wood structure without a vapor barrier.


so I have to 100% disagree here with "no water"

if you ever cut green wood and air dried it you would know lots of water comes out of wood, quite fast.
almost all of it if you lower the outside air moisture content, with a kiln or de humidifier.

to say not enough or very little one would be more accurate, depending on the locale.
In my double wall hives I have seen sweat on the inside of the second layer/outer layer.
I would also suspect the wood holds water till summer, when the air can carry more out, IE storage.

Almost none "runs down the walls" in my hives.
Again this is all conditional on the location, in Arizona, and here there is very different in hive moisture passages.
most of us are speaking for our locale and our observations, so to quibble with a different locale is of no benefit.

If water is not your issue then you have a good locale, if it is then one needs to mitigate a bit to assist the bees.
BTW cedar holds more water than hardwood.

GG


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## A Novice (Sep 15, 2019)

Gray Goose said:


> so I have to 100% disagree here with "no water"
> 
> if you ever cut green wood and air dried it you would know lots of water comes out of wood, quite fast.
> almost all of it if you lower the outside air moisture content, with a kiln or de humidifier.
> ...


All very true.

I was speaking of Mitchell's model. In his analysis no water goes through the layer of propolis on the inside of the tree cavity. It is like a plastic liner with no gaps in a beehive. That is his model. I'm not saying it is reality. That is his model.

In fact, living trees have a lot of water in them, and usually have a bark layer which is relatively impermeable to water, so they don't lose the water they have dragged up from the roots.
So a colony inside of a living tree is surrounded by wood which is near saturation with water.

As a result, that tree has very high thermal conductivity - approaching that of liquid water - and also very high thermal mass - again approaching that of liquid water.

What I don't know is if trees actively control temperature inside of the tree or not. Probably not, but if they do it would provide another level of complexity.

Mitchell's assumption is that the propolis lining of a tree nest is to keep water in, or that that is its effect. 
So in his model, no water leaves the nest through the walls, as propolis is relatively impervious to water.

However, since the wood surrounding the nest may contain water, it might also be keeping water OUT. That would explain why tree nests are lined with propolis, while box hives are not. Keeping water from being evaporated from the wet wood causing excess humidity in the hive might be the reason for propolizing the walls of the nest.

It isn't possible to determine the thermal conductivity values used in his analysis, but they have a huge effect on the results.

Mitchell doesn't list the properties he is using for his analysis, so I can't tell if he used the published thermal conductivity values for dry hardwood or the values from measuring living trees.

Since the analysis is steady state, the effect of thermal mass or heat storage capacity is not considered.

The one thing I saw clearly was that the bees begin fanning when the absolute humidity reaches about 3 kPa, and the higher it goes, the more determined they are to bring it lower. This wasn't part of his analysis but is in a graph he provided from one of his references.











The obvious conclusion is that 3kPa is the humidity level bees want to maintain, since that is the humidity level they try to maintain. 

Forcing them to operate at much higher humidity levels may be bad for varroa and may even have other benefits.

However, bees living in a tree nest with very high humidity, the entire inside of the nest propolized to keep water out may be like humans living in huts made of sticks plastered over with mud and dung, with a dirt floor, a thatch roof full of vermin, and no heat.

It may be a far more natural way for bees to live, just as the dung plastered hut is a far more natural sort of living situation for humans than a modern house with windows, heat, running water, plumbing, clean floors and a roof, but it may not be better for them.

The only way to figure out what works best for the bees and the beekeeper is to try things which look like they might work and learn from these experiments. Mitchell's analysis suggests some experiments I would love to try, but I will never have enough colonies to run an experiment with controls and generate statistically significant results.

I like your insulated hives. I am thinking of trying something similar.

I don't quite dare try putting a sealed layer impervious to moisture around the entire hive except at the entrance, which is what Mitchell's model of a tree hive is. Maybe it would work, but I think there would be real limits on the size of colony that could live in such a hive.


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## Litsinger (Jun 14, 2018)

A Novice said:


> What I don't know is if trees actively control temperature inside of the tree or not.


Jon:

Have you seen this one?



Litsinger said:


> ... the attached 'Thinking Outside the Box' article by Seeley and Radcliffe addresses some of the questions about whether a well-insulated and thermally-massive envelope is better than the alternative- and I look forward to the follow-up results which will presumably include bees inside the tree cavity.


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## Gray Goose (Sep 4, 2018)

A Novice said:


> What I don't know is if trees actively control temperature inside of the tree or not. Probably not, but if they do it would provide another level of complexity.


Yes they do, in spring if you watch trees that have sap run back and forth, like Maples, they melt around the base where the root ball is. This is due to the sap in the tree top is in the sun all day , then sinks to the root system and warms the roots.
similar to your statement that a tree is close to liquid, hence sun warming the sap the sap moving warms all the way to the roots.




A Novice said:


> So in his model, no water leaves the nest through the walls, as propolis is relatively impervious to water.


I am on the other side, I have some quilt boxes with the cloth totally propolized, and the shavings are still wet/moist.
I see propolis as gore tex, moisture can get thru, rain cannot get in. IMO the model is off there.
Mayhap water does not leave but vapor with moisture does.

the hive is very complex, and a simple untested model , can be a starting point , but too many assumptions and the date gleaned is off a bit.

GG


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## A Novice (Sep 15, 2019)

Gray Goose said:


> Yes they do, in spring if you watch trees that have sap run back and forth, like Maples, they melt around the base where the root ball is. This is due to the sap in the tree top is in the sun all day , then sinks to the root system and warms the roots.
> similar to your statement that a tree is close to liquid, hence sun warming the sap the sap moving warms all the way to the roots.
> 
> 
> ...


Agreed.

You almost got the cheeseburger! All you would need to do is redkote the inside of your hive.

My point was the model is of a hive which is a bit unrealistic, and while it brings up some interesting questions, it doesn't answer any.

My other point is that journal articles are a literary style long on misleading half-truths, and short on comprehensible and useful information. This isn't a criticism of the author, who appears quite competent. It is just the game of academia. Reading them superficially can lead to dramatically wrong conclusions. Reading them carefully is a lot of work and rarely worth the effort. There are so many places to slip in questionable assumptions. Sometimes you need to read the references so you can understand their assumptions, and also evaluate if their conclusions are reasonably sound and properly represented in the referencing article. Additionally the actual numerical values of material properties are important in this article, but they are hidden inside of equations and we have no idea what values the author chose. So many places to jigger the numbers to show the results you want to show. Irresistible temptation.

I also think the idea of running extremely high humidity hives (not in winter, where absolute vapor pressure is low even with high/condensing Relative Humidity) is interesting but unlikely.

The idea that a living tree is actually actively cooling the nest of bees inside it is really interesting. It would pretty much ruin the model.

Enjoy your bees.


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## Litsinger (Jun 14, 2018)

A Novice said:


> My other point is that journal articles are a literary style long on misleading half-truths, and short on comprehensible and useful information.


As Carl Sagan famously opined, _'[Science] works. It is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything. It has two rules. First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless. Second: whatever is inconsistent with the facts must be discarded or revised. We must understand the Cosmos as it is and not confuse how it is with how we wish it to be. The obvious is sometimes false; the unexpected is sometimes true.'_


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## A Novice (Sep 15, 2019)

Litsinger said:


> As Carl Sagan famously opined, _'[Science] works. It is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything. It has two rules. First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless. Second: whatever is inconsistent with the facts must be discarded or revised. We must understand the Cosmos as it is and not confuse how it is with how we wish it to be. The obvious is sometimes false; the unexpected is sometimes true.'_


Science is a game.

A game which Carl Sagan played well, and became wealthy, without contributing anything useful I am aware of, other than entertaining misinformation.

Applied sciences - those that produce useful results and exist for no other purpose - sometimes approach the ideal conditions he cited. Pretty much all academic science is about building careers and kingdoms and has nothing to do with making things that work. Even people who are honorable and well intentioned, if they become part of academia, are compelled to play the game by its rules. The rules are:

Support the positions of your faction
always praise "science"
Get as much grant money as you can.

"I am the science". A. Fauchi. (Hubris stated as fact)
There will be no artic sea ice by 2010. A Gore. (Nonsense stated as fact)
You are made of star stuff! C. Sagan. (speculation stated as fact)
It all started with a big bang. S. Hawking (Unsupported theory stated as fact)
Life evolved from non-life. R. Dawkins (statistical impossibility stated as fact)
And let's not even discuss the science of gender.

However, all of the above is "science".

None of it is useful or testable. All of it makes scads of money for its purveyors, who otherwise would be largely unemployable. (Carl Sagan would have made an OK used car salesman, and Al Gore was somewhat successful as a politician, but most of his money comes from "science".)

Science that works to produce a specific end - like improving spatial resolution in ultrasound images - where progress is measurable and posers get sanctioned - is real. 

Carl Sagan draping himself in the priestly robes of "science" which gained their sacred virtue through the efforts of people like Euler and Gauss and Newton and Kepler and Heaviside - who actually figured things out - is deeply offensive to me. It would be like Bill Clinton (or Donald Trump, if you prefer) wearing a US army uniform replete with medals - silver stars, purple hearts, even a medal of honor. He has not earned it.


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## Litsinger (Jun 14, 2018)

A Novice said:


> Science is a game.


Jon:

I do think I know where your coming from and I agree with many of your sentiments. 

My point, specific to the paper under consideration is that while we can (and should) poke holes in the assumptions made and conclusions reached, this type of systematic analysis beats the alternative, which is speculation.

Consider this an open invitation to post competing research and/or field trials that suggest that thin-walled assemblies and/or copious ventilation are better in certain environments- I am interested in reading them in good faith.


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## Litsinger (Jun 14, 2018)

In consideration of this topic, I contacted Mr. Mitchell and asked him four questions.

He recently responded, so I have included my questions and his responses for consideration.

1. Based on the empirical results of the studied colony and the corresponding modeling, what would you suggest is the 'preferred' relative humidity level that a colony would like to maintain during active brood rearing if the envelope and the internal resources would support it?

A. _honey bees have multiple goals with regard humidity 50-60%RH @ any temperature for honey ripening, 80% to 90%RH @34c for brood 75%RH @34C for lounging around. 
The honey bees use microclimates within the nest formed by the comb and their bodies to create different humidities and temperatures. This makes putting in just a few sensors in nest difficult if not impossible to interpret. The key things to understand is that in temperate climates 1) its very energy expensive for the bees to raise nest humidity and cheap to lower it. 2) open honey cells need humidity 50%-60%. 3) high heat loss hives are acting as a dehumidifier._

2. A position has been posited that additional thermal mass might not represent a net benefit to colonies in temperate climates in conditions where the ambient temperature (and presumably the enthalpy) are lower than that within the broodnest. In other words, we would be effectively 'trapping heat in' by resisting conductive heat transfer as opposed to the Saudi study where it might be safe to assume that the ambient temperature is higher than the cavity temperature (i.e. we want to resist skin gains from outside to inside). 

A_. Its a disadvantage to new colony but an advantage to an established. _

3. During the active season, what would your research suggest is the primary mode of heat transfer?

A. _heat transfer is primarily conduction and evaporation. In heat transfer the dominant role of the entrance is the removal of water vapor not the heat capacity of the circulating air._

4. What your thoughts about the exclusion of solar gain in the model?

A. _Honey bees are known to preferentially select nests that are shaded. _

He concludes, _Honey bees in their natural environment have what engineers might call "a well designed solution". I think it would be a good thing for bee keepers to imitate as much of that solution as practical. _


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## A Novice (Sep 15, 2019)

Litsinger said:


> In consideration of this topic, I contacted Mr. Mitchell and asked him four questions.
> 
> He recently responded, so I have included my questions and his responses for consideration.
> 
> ...


Interesting questions.

With regard to question 1, it seems more relevant to speak about absolute humidity, since relative humidity is a strong function of temperature, and also because the posited beneficial effects of high humidity happen at very high absolute humidity. The only evidence I have seen is the normalized fanning response curve from the original article, which appears to show bees prefer an absolute humidity below 3 kPa, and begin fanning (possibly to lower absolute humidity) at about that level. It is also possible that the external humidity was about 3 kPa, and so heat rejection as water vapor is ineffective below that value, so fanning is ineffective. Not enough information. His specific points to remember are interesting, though they are rather broad generalizations which I am not persuaded are generally applicable.

With regard to question 2, adding thermal mass does not impede heat transfer, and in fact is ignored in the model in the paper because the model is steady state, and in the steady state thermal mass has exactly zero effect on the results. Adding insulation would have the effect of impeding heat transfer, but that is a different thing altogether. It isn't clear if the answer is regarding adding thermal mass or adding insulation, and also isn't clear why the advantages and disadvantages are as stated.

With regard to question three, the answer makes sense. Without knowing the size of the entrance, the volume of the cavity, and the insulative properties of the nest it is hard to say which is larger between conductive heat loss and evaporative heat loss. (water vapor leaving through the entrance(s).

With regard to question 4, while this is true, it is also true that experience teaches that hives generally do better in sunny locations. This may be due to other factors than thermal management. It is also true that the results are less applicable for hives located in sunny locations since solar heat loading is likely significant for those hives.

His summary is a philosophical statement. It provides some insight into his world view, and why his research is heading down the path it is on. It may be correct. 

I tend to reject romanticism - the idea that things in their natural state are somehow better or nobler, and that attempts to domesticate or civilize result in degradation and weakness. We live in a fallen world where nothing is quite what it should be, and life is difficult for all living things. All of creation groans in anticipation.

I would expect that a colony of bees in a tree is likely to be somewhat more like a group of people living in stick huts plastered with cow dung and mud, with thatch roofs, dirt floors, no heat, no windows. That is a different philosophical viewpoint.
It is based on the understanding that the natural world and the natural impulses of ourselves and other creatures are corrupt. 

Always interesting.

Still haven't seen anything in the discussion which would motivate me to consider changing my hive designs, except for the hives Grey Goose built. He roughly doubled the thermal mass, and increased the insulative value by maybe 7X a standard box. Not entirely clear on ventilation, but it looks significantly restricted too.

Looking through patent literature, there have been at least two previous rounds of insulating hives since 1860. It is sort of like wallpaper - everybody likes it until they've had it a few years. The bees do a bit better, but the expense and difficulty for the beekeeper is significantly greater, especially at scale. As a result, the industry trends toward a more minimalist and inexpensive design - the Langstroth hive. It is better than a mud hut.


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## Litsinger (Jun 14, 2018)

A Novice said:


> As a result, the industry trends toward a more minimalist and inexpensive design - the Langstroth hive.


On this score, the good Reverend had this to say:

_"I recommend, however, a construction which, although somewhat more costly at first, is yet much cheaper in the end. Such is the passion of the American people for cheapness in the first cost of an article, even at the evident expense of dearness in the end, that many, I doubt not, will continue to lodge their bees in thin hives in spite of their conviction of the folly of doing..."_


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## Litsinger (Jun 14, 2018)

Litsinger said:


> On this score, the good Reverend had this to say:


And if anyone is interested in Reverend Langstroth's thoughts on hive construction, look for Chapter 8 of his seminal 'The Hive and The Honey Bee'. It is available online as public record. 

I think it is safe to say his views mirror Mr. Mitchell's in terms of observing nature to inform best practices regarding hive construction and apicultural management.


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## A Novice (Sep 15, 2019)

Litsinger said:


> On this score, the good Reverend had this to say:
> 
> _"I recommend, however, a construction which, although somewhat more costly at first, is yet much cheaper in the end. Such is the passion of the American people for cheapness in the first cost of an article, even at the evident expense of dearness in the end, that many, I doubt not, will continue to lodge their bees in thin hives in spite of their conviction of the folly of doing..."_


True. Langstroth was a proponent of dual walled hives, and his hive construction was quite complex. In fact, no one has sold an actual Langstroth design hive commercially since about 1920. His hive design was not at all portable, and frames were spaced by hand, as was his preference. 

I suppose Langstroth wanted people to buy his hives, though they weren't as practical as the standard commercial "Langstroth" hives which became popular.

I looked into building a hive according to Langstroth's design, but it was overly complex. The features to trap wax moths were not useful, for example. At the same price, I would take a box jointed standard hive every time. 

Not to minimize Langstroth's contribution to beekeeping, but some of his ideas (like unspaced frames) were not for everybody.


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## Litsinger (Jun 14, 2018)

A Novice said:


> it seems more relevant to speak about absolute humidity...


Jon: While I don't disagree on balance, I expect the reality on the ground is that we can't really talk about humidity in either an absolute or relative sense without also talking about the associated temperature, at least as regards to a nest cavity during the active season. I expect this is why Mr. Mitchell couched his response in both RH and T, as they are values that most folks are familiar with and are also values that are relatively easily measured in the field.



A Novice said:


> adding thermal mass does not impede heat transfer...


This is certainly true in a theoretical sense, but like the mud hut in your example I believe Mr. Mitchell's base frame of reference is the bee's natural home, which typically happens to be both thermally massive and highly resistant.



A Novice said:


> ... experience teaches that hives generally do better in sunny locations.


Do better in what way? It might be safe to assume that they may accumulate more surplus in some environments all other factors being equal due to earlier foraging flights, but is it clear they are healthier or that they benefit from more direct solar gain in any other observable metric?



A Novice said:


> It is based on the understanding that the natural world and the natural impulses of ourselves and other creatures are corrupt.


Philosophically, I agree with you that the world is bent and twisted- but I am reminded that even in the mist of the corruption:

Romans 1:20 - For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse. 

And as King David reminds us:

Psalms 19:1-2 - The heavens are telling of the glory of God; And their expanse is declaring the work of His hands. Day to day pours forth speech, And night to night reveals knowledge.


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## A Novice (Sep 15, 2019)

Litsinger said:


> Jon: While I don't disagree on balance, I expect the reality on the ground is that we can't really talk about humidity in either an absolute or relative sense without also talking about the associated temperature, at least as regards to a nest cavity during the active season. I expect this is why Mr. Mitchell couched his response in both RH and T, as they are values that most folks are familiar with and are also values that are relatively easily measured in the field.


The virtue of absolute humidity is that it tends to be relatively constant throughout the hive, with the exception of in the brood cells where there is a very wet liquid being fed, creating a wetter microclimate. It is also more relevant to the article which began this discussion, as the premise is that relatively high absolute humidity is beneficial. It is tedious to convert to absolute humidity to compare with the relevant value of 4.3 kPa. One thing which is interesting is that the absolute humidity in the brood cells, where varroa reproduce, is pretty much always higher than 4,3 kPa, unless it drops precipitously once the cells are capped. This opens the question of the mechanism by which high humidity impedes varroa reproduction. If it is due to effects on phoretic mites, then raising the nest humidity would be potentially helpful. If it is due to effects inside of the sealed brood where mites actually reproduce, then it seems doubtful that any changes to the humidity of the hive at large would produce any benefit.




Litsinger said:


> This is certainly true in a theoretical sense, but like the mud hut in your example I believe Mr. Mitchell's base frame of reference is the bee's natural home, which typically happens to be both thermally massive and highly resistant.


In practical applications people keep bees in hives, and for obvious reasons do not want bee boxes composed of 6 inches of hardwood unless it produced some significant advantage. So for actual hive design, it is useful to understand these two factors separately. My comment was more directed at the question however. These two things are as different as air and water.



Litsinger said:


> Do better in what way? It might be safe to assume that they may accumulate more surplus in some environments all other factors being equal due to earlier foraging flights, but is it clear they are healthier or that they benefit from more direct solar gain in any other observable metric?


My understanding is that the primary reasons for keeping bees in full sun are disease related. Bees in sun have fewer problems with chalkbrood, nosema, sacbrood, etc. Also manage hive beetles better. That is the conventional wisdom.
I doubt that earlier foraging makes any difference for gathering nectar, but that is a separate discussion. 



Litsinger said:


> Philosophically, I agree with you that the world is bent and twisted- but I am reminded that even in the mist of the corruption:
> 
> Romans 1:20 - For since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse.
> 
> ...


True enough. Even the ruined remains of creation show the power of the creator. But things are not the way they should be, and we can easily see that.

My point is that the natural state of some animal is not the ideal state, or even close to it.

"house" cats are amazingly well adapted to live in the wild, and feral cats do very well. However, their lifespan is about 5 years. Anywhere they live. Except if they live in houses, are taken to the vet, and fed cat food from a can. Then they live about 15 years.

The same is true for any species in captivity. By any metric, we can improve their health and longevity by keeping them in unnatural settings.

We can learn from how they live in their "natural" condition, but it is romanticistic nonsense to idealize it.


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## Litsinger (Jun 14, 2018)

A Novice said:


> We can learn from how they live in their "natural" condition, but it is romanticistic nonsense to idealize it.


Jon:

Thank you for your feedback. You often make this point, and I do think I understand where you are coming from. 

I do expect however that it is easy to conflate the dynamics of an animal living in a wild state with those living under active human management.

In other words, we are not here comparing bees living in a wild and unmanaged setting versus those living in active management. We are rather comparing managed bees and whether the lessons we can learn from their natural environment can inform our beekeeping practices - are they healthier living in a managed cavity which more closely mimics their natural home versus the alternatives, all other things being equal.



A Novice said:


> The virtue of absolute humidity is that it tends to be relatively constant throughout the hive...


If I interpret Mr. Mitchell's research correctly, he would suggest that the absolute humidity within the hive is not constant. He often refers to the analogy of a 'nursery next door to a sugar refinery'. If we look at his ranges noted above:

Broodnest - 34 C @ 90% R/H = 4.79 kPa
Periphery - 34 C @ 75% R/H = 3.99 kPa



A Novice said:


> These two things are as different as air and water.


I do not disagree- but for the purposes of this discussion, we are talking about:

Thin wall hives - Low thermal inertia / low resistance
Tree cavity - High thermal inertia / high resistance



A Novice said:


> My understanding is that the primary reasons for keeping bees in full sun are disease related.


I spent as much time as I dared looking for scholarly research on the topic of sun / shade and disease resistance. The best I could come up with is Ms. Rusty Burlew's write-up below:









Sun or shade: which is best for the bees?


Sun or shade for bees? Which is best? Beekeepers will likely opt for hives in full sun. But given a choice, honey bees will pick a home in the shade.




www.honeybeesuite.com





That said, if you are aware of any studies comparing colony health and performance with sun versus shade as the variable, I would genuinely like to read them. Here is the only research I could find on the subject, but it relates to Arizona conditions:









Shade and water for the honey bee colony : Owens, Charles D., 1921- : Free Download, Borrow, and Streaming : Internet Archive


Cover title



archive.org


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## Gray Goose (Sep 4, 2018)

A Novice said:


> it is also true that experience teaches that hives generally do better in sunny locations.


Not mine.
the hives I have under a roof and with 3 walls, IE no sun, did the best this and last year, by at least a super of honey, on production, and this past winter were 5 of 6 surviving, 87 ish percent survival. My full sun or out in the wind hives single wall were 2 of 6 surviving or 33%



A Novice said:


> adding thermal mass does not impede heat transfer,


that was most of the reason I did the extra thick walls.
I guess if the door is big enough then the wall thickness matters less, but bees tend to shut openings deemed too big.

as far as cost and selling the double wall hives, it is more than X2 of wood as the outside wall is longer than the inside.
the corners and fasteners , I used screws, are X3, with the "many new" shoppers not knowing about this topic out of the gate the 2.x times for Hive price would minimize sales.
IMO looking at sales and what is commercially build is not indicative of what "the best hive for your locale is"
southern 1/3 of the US,, single wall is fine as this climate is more close to the place the bees came from.

In general where you are matters.
and if one were to know in advance that they were keeping bees for 10 years and live in the north 1/3 of the US or Canada, then buying bees once and spending double on the hive , or spending 1/2 on the hive and buying bees 3 or 4 times, one may find the "costs" similar. factoring in a crop on first year splits, packages, and NUCs as very small if any further pushes the cost structure to have the thin wall Hives as the expensive solution. Also as @crofter has discovered less ventilation and more insulation lowers honey consumption, allowing an even bigger harvest.

BTW first snow here today...

GG


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## Litsinger (Jun 14, 2018)

Great interview with Cliff Struhl of Hive Smart Designs on the subject of Pragmatic Beekeeping - the underpinnings of which align with much of what has been discussed recently in this thread:









Pragmatic Beekeeping with Cliff Struhl (S5, E15)


In this week’s episode, we visit with Cliff Struhl about his thoughts on better ways to keep bees than is generally done today (and the past 170 years). …




www.beekeepingtodaypodcast.com


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