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Condensation and varroa! Missing link to survivalists
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zaunreiter
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PostPosted: Tue Jan 17, 2012 9:55 pm    Post subject: Condensation and varroa! Missing link to survivalists Reply with quote

I always wondered, why feral honeybee colonies survived in hollow trees for 12 years and more throughout the world, while in hives they die.

I think I got something!


> http://www.archive.org/details/cu31924003100306

I just read several times over the book, re-read again and again - and it makes perfect sense and fits in many observations I did. It explains a lot.

I think, there could be something into it for hive improvements. Making it a condenser hive - an even better one as the construction hive by Clark.

For example we could use a clay roof in summer during flow.

It also gives some explainations why bees in hollow trees survive varroa, while transfered in hives the bees die off varroa. Condensation properties of the hive may be the difference! Because without condensation, the water has to be carried in - this may lead to less brood food sap (gelee royal for the workers, what is the right word again?). Because the brood food is made with pollen and water!

Missing water through condensation, little water collection during a main flow may lead to less brood food per cell, making a difference to varroa population! Because the less brood food, the earlier the mite awakes from it's sleep in the brood food and starts oogenisis. Leaving more time to reproduce, multiplying itself from 1.7 up to 3-4 times.

That could be it.

Bernhard
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newwoman
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PostPosted: Wed Jan 18, 2012 7:11 am    Post subject: Reply with quote

Gosh Bernhard what a marvellous article-it cetainly takes a bit of thinking about

Quote:
gelee royal for the workers, what is the right word again?

(I think in English you might mean Royal Jelly)

Pat Laughing
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Viggen
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PostPosted: Wed Jan 18, 2012 8:41 pm    Post subject: Reply with quote

As soon as the site come back online tomorrow I look forward to reading the article.
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Gareth
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PostPosted: Wed Jan 18, 2012 10:31 pm    Post subject: Reply with quote

Fascinating thought, Bernhard.

After a quick read of Clark's book, I see he mentions two further facts:

    When moisture from the hive condenses IN the hive, the heat that is given up during condensation ('latent heat') remains within the hive. This heat helps to maintain the temperature of the hive rather than being lost to the outside air. Varroa doesn't like warm conditions.

    The air inside containers remains drier if any moisture that is present can condense on the walls of the container. Clark uses the example of refrigerators staying dry as long as moisture can condense on the walls (and drain out through that little hole at the bottom of the back).


On this analysis, a hive that has an impermeable inner coating (such as propolis) on its walls stays both warmer and drier than one that has vapour permeable walls or a vapour permeable quilt.

Isn't this the opposite of the idea behind the permeable Warre quilt?

I'm off to have a read about Roger Delon's Stable Climate hives .....
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zaunreiter
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PostPosted: Thu Jan 19, 2012 1:56 am    Post subject: Reply with quote

Do the math.

Air of 20 degree Celsius holds 10 gram of water - per cubic metre!

http://upload.wikimedia.org/wikipedia/commons/9/91/Feuchte_Luft.png

One Kilogram of honey needs the evaporation of three kilogram of water since nectar contains about 60 to 80 % of water and honey just 20 %.

To suck up the 3,000 gram of water at an air temperature of 20 degree Celsius about 300 cubic metre are needed.

One empty (!) Warré hive box holds 0.02 cubic metre!

You need the air mass of 15,000 empty Warré hive boxes, to get rid of that water. Empty hives and of course the air mustnot contain any water, which is not the case in outdoor conditions. So you need even more air to suck up that water.

That doesn't work through ventilation, not even with heavy overdose ventilation.

Think of the humid conditions in May, and this exactly explains, why swarms take off after rainy days.

It's condensation the bees work with.

http://upload.wikimedia.org/wikipedia/commons/thumb/2/2f/Dewpoint-RH.svg/500px-Dewpoint-RH.svg.png

Bernhard
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Sir David
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PostPosted: Thu Jan 19, 2012 9:19 am    Post subject: Reply with quote

mmm am trying to get my little brain round this one
It appears from what you are saying Bernard that the bees
a) have a lot of work to do to ' dry out ' the honey
b) heat and air flow is the key to this .

I am assuming that bees in 'super organism ' mode can regulate the conditions in the hive . Is this where the Warré Quilt comes in ?
What can we do to help the bees ? Would replacing the quilt material help ?
A summer quilt ( soaking up water Charcoal ? Wool ? something like a wick ) vs a winter quilt( insulation )
Wink
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Sir David
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PostPosted: Thu Jan 19, 2012 9:37 am    Post subject: Reply with quote

Just another thought . If the Bees are living in a tree that is still living ,would the tree its self absorb water from the nest ? I know trees spend a lot of energy effectivly pumping water up to and out of the leaves from the roots . An active system could remove a lot of water this way , if you do the math trees shift a lot of water around .
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zaunreiter
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PostPosted: Thu Jan 19, 2012 10:53 am    Post subject: Reply with quote

Sir David wrote:
a) have a lot of work to do to ' dry out ' the honey


Yes, but also to provide water for brood food production.


Sir David wrote:
b) heat and air flow is the key to this .


Not just. Heat yes. Air flow - no! The opposite. The air flow = ventilation. Ventilation is needed but just a little. Condensation actually is drying out the air! Much more than ventilation ever could. See calculation above.

So instead of a wick or sponge, you need a safe condensation surface. I guess the wall is best for this. Because the floor has a lot of debris fallen onto, which would turn into slime. Bees won't take this for food production for obvious reasons. Overhead condesation may lead to dripping water onto the bees. On the sides the condensation would be best.

So to design condensation into hives, you have to insulate just a little. I read about phase-change-material - and this where wax comes into! Wax is the perfect phase-change material. 4 cm wax coating provides heat storage like a solid 30 cm brick wall! See: http://en.wikipedia.org/wiki/Phase-change_material

So one construction element could be the coating of the inner sides with a thick layer of wax and on it a layer of rosins/propolis coating. Probably as efficient as a polystrene hive!

That would keep the heat inside the hive, making it warmer than the outside air, thus producing condensation!

Next thing would be to eliminate the over-ventilation. By making the lid and box junctions as airtight as possible.

It'd be good to have an additional surface at the wall which is cooled some way to produce condensation there - to keep the air dry and provide an inhive water source. Thinking about a window glass pane with some cooling mechanism. The window serving two purposes: condensation surface and observation possibility.

Any ideas welcome.

Bernhard
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zaunreiter
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PostPosted: Thu Jan 19, 2012 11:40 am    Post subject: Reply with quote

Warm air holds most of the moisture and it raises. Maybe some sort of topbox condensation surface would be a good thing. On the sides of the topbox. As a honey chamber, where nectar dries quickly.

On the sides of every box it would be next to the brood, don't think that is good. At least with active cooling.

Bernhard
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Sir David
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PostPosted: Thu Jan 19, 2012 1:36 pm    Post subject: Reply with quote

How about a substance that is cool because it is cooled by the evapouration of water . I was thinking terracota . Plants are often better in terracotta pots because they dont cook in them unlike plastic pot in hot weather, the romans stored wine in then as it kept cool . Since water will soak in there is no chance of water dripping into the hive.
Instead of the quilt a terracotta tile in summer? just a thought
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madasafish
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PostPosted: Thu Jan 19, 2012 1:54 pm    Post subject: Reply with quote

This explains why poly hives are so effective.
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CCD
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PostPosted: Thu Jan 19, 2012 5:17 pm    Post subject: Reply with quote

This all seems to focus on the summer time when there are a lot of active bees to remove the water physically from the walls/ roof etc.

What about the winter time? I thought that condensation and moisture was the last thing that one should have in the hive! Poor ventilation, non-breathable walls, little insulation etc. all seem to point to wet hives and dead colonies! This is shown by the greater winter survival with open, mesh bottoms of hives. Skeps too allow for dissipation of moisture through the hive wall and skeppists report very happy, lively hives.

I am not saying the condensation theory is wrong, I just cannot see how these opposites can both be true.


(By the way, I asked my local beekeepers if they noticed much difference between the winter survival performance of wooden and poly hives and there was very little to distinguish between them. Poly hives being only slightly better. I think the advantages are mainly in lighter weight, lack of rot/maintenance and perhaps price.)
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zaunreiter
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PostPosted: Sun Jan 22, 2012 12:01 am    Post subject: Reply with quote

http://upetd.up.ac.za/thesis/submitted/etd-10022009-135223/unrestricted/dissertation.pdf


Ellis did a proper work, also not looking at condensation. He observed the intake of condensation water, though. 

He also points out, that a feral hive has been found with a relative humidity of 75%.

On top there is a study that no varroa survives a humidity of 80 %. 

And - there is a difference of the humidity within a cell and inside the hive. Inside the cell humidity is much higher, and in fact it is needed for brood survival.

And - old comb holds 11 % of it's weight in water. New comb only 3 %. The old comb is a buffer and releases water if hive air humidity levels decrease. 

Pretty interesting stuff, I think we have a nice hypothesis to work on. Not in frame hives, but in fixed comb hives.

What do you think - is there a different humidity in small cells versus bigger cells?

I think: YES. Which could be why drone cells (being larger) are preferred by mites. 

Back to small cells then. Maybe we could boost the effect of small cells by designing in condensation into hive construction.

Bernhard
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Gareth
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PostPosted: Sun Jan 22, 2012 6:17 pm    Post subject: Reply with quote

Bernhard

I'd like to read that dissertation, but can't get the file to open. Could you send me a copy if I PM you an email address, please?
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Gareth
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PostPosted: Sun Jan 22, 2012 6:48 pm    Post subject: Reply with quote

zaunreiter wrote:

On top there is a study that no varroa survives a humidity of 80 %. 

Bernhard


That study is available here and shows that, at 70% humidity, Varroa reproduce at the highest rate, whereas at 80% they almost stop reproducing completely. In other words, every 1% increase in humidity above 70% in the brood area hurts Varroa.

This suggests that a perfect hive for Varroa control would be one that allows the bees to maintain as a high a humidity as possible in the brood cells.

So


    Small entrance
    No through ventilation
    No bottom screen
    Old comb if possible (to buffer humidity)
    Small cells??
    Non-porous hive walls??

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DavesBees
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PostPosted: Sun Jan 22, 2012 10:55 pm    Post subject: Reply with quote

Gareth hit on this above but I would add the propolis to the mix. We know they want to coat the entire inside of the hive with it. That would provide the vessel for condensation on the walls. The high humidity coupled with ample propolis may provide an inhospitable environment for mites and other vectors as well. The unanswered question with survivor bees in a tree is; did it take a couple of tries to get it up to a healthy level. Or do the bees start in a tree and die the first season, while providing a jumpstart for a swarm to move in the following season. This second colony may also succumb to mites but provided the additional work on the hive that will catapult swarm no 3 to become successful survivor bees. If these 3 swarms came from the same survivor colony and over three seasons colonized another tree then they were successful. Some folks would view this as 2 failures in a row; I say it all just natural progression.
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zaunreiter
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PostPosted: Mon Jan 23, 2012 9:07 am    Post subject: Reply with quote

That is a good thought.

I want to add my theory which certainly fits the picture: Prime swarms with the old queens are the nest builders, while casts (young queens) only thrive in already build nests.

If a cast gets stuck into a new place, it'll die off. If it finds an already built-up environment it'll thrive.

Bernhard
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DavesBees
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PostPosted: Mon Jan 23, 2012 11:26 pm    Post subject: Reply with quote

Bernhard,
I like the way you think.
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FollowMeChaps
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PostPosted: Tue Jan 24, 2012 8:54 am    Post subject: Reply with quote

Some great thinking going on here guys, thanks for starting it Bernhard. I think I'm a believer already as it serves to reinforce the 'hive atmosphere' argument (Nestduftwärmebindung) on which I'm totally sold.

Can I ask what you mean by an 'already built up environment' Bernhard? Do you just mean a nest where previous occupants have already plastered the walls with propolis/wax or are you also anticipating some previous combs left behind as well? Again this all makes so much sense.

Dave, your catapult theory seems a good one also.
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Barry Jackson
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PostPosted: Tue Jan 24, 2012 10:44 am    Post subject: New Swarms Reply with quote

Prof. Seeley's maintains that the survival rate of new swarms in Feral colonies is 25%. Presumably this could be prime or secondary, but difficult to study in tree colonies 7 metres high. Conditions and sites of hives in feral colonies seem to require South facing entrances and a distance of approximately 250 metres between colonies. Once established the forest communities have increased in spite of varroa over the 30 year plus period.
Barry
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biobee
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PostPosted: Tue Jan 24, 2012 10:51 am    Post subject: Reply with quote

This fits nicely with my plan for lowering the floor mesh and adding a deep layer of wood shavings, which would absorb excess moisture and maintain a higher humidity. The one hive I have done this on so far is certainly doing well so far.

Pics here - http://www.biobees.com/images/?dir=deepFloor - although MKII will simply be a removable extension of the side walls using 4"x1" timber. This will also allow bees to extend their comb a little deeper without feeling a draught.


Last edited by biobee on Tue Jan 24, 2012 11:02 am; edited 1 time in total
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recon
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PostPosted: Tue Jan 24, 2012 11:00 am    Post subject: Reply with quote

This it's rather interesting..

There is a chap, can't remember his name, he fills a miller feeder up with water and leaves that at bottom of hive.
I think he leaves it there the year round..

Will have to find link... Was a couple of years ago,i read it. Any one seen it?
He had good survival rates..

DD
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biobee
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PostPosted: Tue Jan 24, 2012 12:24 pm    Post subject: Reply with quote

recon wrote:
This it's rather interesting..

There is a chap, can't remember his name, he fills a miller feeder up with water and leaves that at bottom of hive.
I think he leaves it there the year round..



Hopefully with some kind of mesh over it, or he will have a lot of drowned bees...
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biobee
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PostPosted: Tue Jan 24, 2012 4:01 pm    Post subject: Reply with quote

Maybe worth fitting one of these http://tinyurl.com/6npjtc2 to every hive? Zero power consumption.
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Gareth
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PostPosted: Tue Jan 24, 2012 4:30 pm    Post subject: Reply with quote

biobee wrote:
Maybe worth fitting one of these http://tinyurl.com/6npjtc2 to every hive? Zero power consumption.


To be meaningful, what needs to be measured is the humidity inside the brood cells. It seems that the humidity can vary considerably in different parts of the hive.
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biobee
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PostPosted: Tue Jan 24, 2012 7:29 pm    Post subject: Reply with quote

Gareth wrote:


To be meaningful, what needs to be measured is the humidity inside the brood cells. It seems that the humidity can vary considerably in different parts of the hive


Tricky... but wouldn't that be closely related to the humidity in the general vicinity of the brood nest? I already have a sensor that would fit there.
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Gareth
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PostPosted: Tue Jan 24, 2012 9:36 pm    Post subject: Reply with quote

biobee wrote:

Tricky... but wouldn't that be closely related to the humidity in the general vicinity of the brood nest? I already have a sensor that would fit there.


I can imagine that the humidity 'in the vicinity of the brood nest', say at its edge, might vary from that in the core brood nest and also from that inside the cells. And the humidity in the cells could itself vary between the edge and the core of the brood nest. Size of cell could be relevant, eg small worker cells vs larger worker cells vs drone cells, as well as position of the cells.

I'm not saying that a series of measurements taken over a season would not be interesting, merely that one would need to be careful about extrapolating from them.
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biobee
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PostPosted: Tue Jan 24, 2012 10:37 pm    Post subject: Reply with quote

Here's a possible way this could be further investigated - http://www.biobees.com/forum/viewtopic.php?p=70644#70644
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DavesBees
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PostPosted: Thu Jan 26, 2012 4:14 am    Post subject: Reply with quote

I think you two chaps need to take a deep breath, go to the nearest Pub, then sit down and extrapolate a pint before you hurt yourselves. Laughing
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melissabee
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PostPosted: Thu Jan 26, 2012 12:28 pm    Post subject: Reply with quote

So, do you have a kind of prototype for such a hive in mind? I'm trying to follow your discussion and have some design in my mind as well but I'm sure I've misunderstood something.

Could a poly hive be somehow modified in order to get all those features you are telling us?

Or am I too early with wantinga finished design?

melli
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