Cold Weather and Ventilation Experiment

[Ben Framed]

I have read MUCH about hive venation, hive insulation, new hives made with insulated type materials, condensation of the hive concerns in winter; etc.
 
I tried something suggested by a fellow that has been keeping bees most of his life, lives locally, and knows a lot about bees. Last summer I added a pebble beneath each of my hive tops for ventilation as he suggested in the heat of the Summer. I also did something which I considered non-logical for the winter months. He suggested hives need ventilation even in winter as summer. So I tried it on a 'single' 'sacrificial' hive for the sake of learning.

We had a colder than usual winter here with many days not rising above freezing for weeks at a time. The coldest that I recall this winter was 16F. I did not expect this experimental hive to survive for this simple reason of "added ventilation".

I am posting a picture of that hive and its top and the ventilation pebble which is still in place. I am happy to say the hive is thriving!

Phillip




 

[NigelP]

It was a common misconception in the UK to lift the crown boards with matchsticks for the winter, thus exposing the colony to a through draft of cold air all winter long. Many survived but many succumbed.
Logic says the bees are trying to maintain a cluster temperature throughout the winter which requires energy. This cluster loses heat into the surrounding hive by simple laws of physics. How does it make sense to put the cluster in a wind tunnel? Where the cluster will lose heat even faster, needing the heater bees to consume more stores to generate enough heat to keep the colony alive. It pays testament to the bees ability to survive even when beekeepers do  (IMHO) strange things to them that tax their ability to get through the winter.

[Ben Framed]

I agree with your logic. That is why I tried it with just one hive. Yet the older beekeeper described, insist of the importance of hive ventilation, even in winter in my area. I am not recommending this at this time. However the experiment, was done partially with the following in mind.

Several of us here at beeaster have discussed varroa mite treatments using heat. Honeypump, if I remember correctly, once touched on the question of the opposite, which is cold. I do not recall the conversation going any deeper in that direction at the time, but I for one did give it some thought. (When TheHoneyPump speaks I try to listen closely). Though he did not suggest this experiment, as I recall, but did briefly mention what if cold vs varroa instead of heat. Though I did not do a mite count on this hive going into winter, I now wish I had done so in order to compare the count to this same hive now, coming out of winter. 

Another question in answer to this experiment, is buying expensive special made insulated hive bodies really necessary? Or (might)  they be more for the benefit of piece of mind of the beekeeper than that of the need of bee., at least in my area?  (If concern for cold is the primary reason for purchasing insulated hive bodies).
I am not referring to weight concerns.

We have members here from all types of climates. I described the climate of my area past winter. When I began keeping bees, I was concerned that my bees might not make it through winter if I did not do everything possible to make sure they were draft free. I even went as far as buying sheets of thick insulation board, cut to fit the top box, insuring no draft. The bees (to my frustration), chewed tunnels in that insulation board which I had sandwiched on top of the hive yet beneath the top themselves creating a certain amount of draft. (Not to the extreme as shown in the picture, but a tunnel of cold draft throughout the hive in spite of my effort (to help them stay warm). 😊

Phillip

[The15thMember]

I think there is a difference between draftiness and ventilation.  In my microclimate, in my equipment at least, the bees need ventilation.  Summer and winter I'd have water dripping on the bees if they didn't.  Both my summers and winters are pretty mild, so I use screened inner covers in the summer and moisture quilts in the winter.  In the winter when the bees are clustering, the moisture quilt provides ventilation and absorption of excess moisture in a way that minimizes draftiness.  I agree with Nigel that a draft around a winter cluster is not ideal and feel like a moisture quilt provides a good balance between the two evils of moisture and draftiness in my particular climate. 

I'm thinking about getting some more heavily insulated equipment to test out this theory, but I'm wondering if it's actually poorly insulated hives that need ventilation.  In my case at least, ventilation is an attempt to control excess moisture; the warm moist air exits the hive instead of condensing at the top.  But I'm wondering if the water vapor in the air wouldn't condense at all in a hive environment that was better insulated.  Take a winter cluster for example: the bees' heat and exhalation produces warm moist air which rises to the top of the hive where it meets the cold inner cover.  The gaseous water vapor condenses into liquid water when it comes in contact with the cold lid, which then drips back down onto the bees.  The same process happens in my area in the summer, when it's humid and the nights are cool.  But if the hive top was better insulated, that warm moist air wouldn't condense on the underside of the inner cover, because the inner surface of the hive top wouldn't be cold in the first place.  This same concept goes back to how wild colonies in trees don't have much ventilation, because a tree is far more insulating than the standard thickness boxes we use in Langstroth beekeeping.       

[Brian MCquilkin]

This Winter My hive configuration was solid bottom boards and no top ventilation. I did add 2" Ridgid foam insulation.  Have to say very happy with the decision not to go with top ventilation. My losses this winter have been 4 hives. I'm a happy camper.

[Ben Framed]

This Winter My hive configuration was solid bottom boards and no top ventilation. I did add 2" Ridgid foam insulation.  Have to say very happy with the decision not to go with top ventilation. My losses this winter have been 4 hives. I'm a happy camper.

Brian, that was my practice before I switched to Mountian camp two years ago. As can be seen in the picture; I have never used an inner cover. I do use Mountian camp as my moisture barrier as well a moisture absorber on top of my frames which I see as beneficial two ways.  For me in my area it is win win. I have had NO problems. Including mold in the hive by using this method, as some have described in other discussions.

As far as draft and ventilation, do any of you remember the discussion we had here a couple years ago on the Topic:  Open air hive. Mr AR Beekeeper told us of an open air hive that survived the winter in his Mountains of Arkansas! Now that is amazing! It gets pretty cold in those hills! From his description cold was not a killing problem, it survived the cold. Now if they had been exposed to rain then they would have most likely perished.

AR Beekeeper

I have seen only one exposed colony that survived over winter here in Arkansas, and that colony was protected by an overhang on a bluff.

He went on to say.

AR Beekeeper

And the next time we see a post that says the bees always know best, remember those photos.

[TheHoneyPump]

Before folks take away or leave any ideas and results on this subject of ventilation, please ensure the understanding is crystal clear that success or failure of each different ventilation configuration is ENTIRELY dependent on geographic region AND on the various micro climates within that region.
Look at the location of the poster in their profile and ask alot of questions about where the beehive is sitting relative nearby buildings and shelter belts before considering to take or leave what is being offered.
IMHO.

[Ben Framed]

Before folks take away or leave any ideas and results on this subject of ventilation, please ensure the understanding is crystal clear that success or failure of each different ventilation configuration is ENTIRELY dependent on geographic region AND on the various micro climates within that region.
Look at the location of the poster in their profile and ask alot of questions about where the beehive is sitting relative nearby buildings and shelter belts before considering to take or leave what is being offered.
IMHO.

Absolutely 100% agreed. I am in no way or by no means suggesting anyone try this. As I stated earlier. This experiment is a result of the conversation we had concerning heat in relation to controlling Varroa mites. You had suggested cold instead of heat. At least now I know that bees can withstand cold in my area with the extra wide gap that I have pictured on the top of the pictured hive in an open field. This includes 6 inches of snow at one time of the season along with temperatures described above.  This post is simply a suggestion that your theory of cold vs Varroa may be very well prove to be worth a try. At least the ground work has been laid for the sake of experimentation.. As stated above I only wish I had done a mite count going into winter. Honestly, I did not expect this hive to survive.

Phillip

[Oldbeavo]

I will try and find a scientific article on ventilation.
The guts of the article was that bees naturally create air flows that flow horizontally across the frames. Using the entrance as the air source.  Any top ventilation will create vertical drafts that upset the natural horizontal air flow of the bees.
We have stopped using lid vents with no problems and the Paradise hives we run have no top ventilation.
My thoughts are that condensation arises when the hive lacks insulation, especially the lid, and that the bees are not packed down tight enough for winter. We almost eliminated condensation by insulating lids, when we get some its due to too much room in the hive.
Look at the Canadian guys who pack down to singles for winter, there is a utube somewhere.
Ventilation is human logic, not bee logic.

[beesnweeds]

No two cavities are the same even with feral colonies. Bees are adaptable whether there is ventilation, no ventilation, upper, lower entrances, 10, 8, or 5 frames.  Ive overwintered hives both ways with no problems.  For me it comes down to low mites/diseases, food stores, and first year queens.

[Ben Framed]

No two cavities are the same even with feral colonies. Bees are adaptable whether there is ventilation, no ventilation, upper, lower entrances, 10, 8, or 5 frames.  Ive overwintered hives both ways with no problems.  For me it comes down to low mites/diseases, food stores, and first year queens.

Well said beesnweeds..... especially the, "For me it comes down to low mites/diseases, food stores, and first year queens.", part. All good points IMHO.

Speaking of mites and the primary reason for this experiment and post; If we stay on top of our mite problems, this should eliminate many other problems which spin off from mites themselves, causing weak and dying bees from the damage mites inflict to our bees themselves by living off of our bees, but also and including viral diseases carried by mites. "Varroa Destructor"
I do not look for this to go anywhere. I posted this for the sake of any who might be interested and inquisitive with open minds seeking advancement in newer ways of treating mites. A direct contrast in heat treatment for mites which many seem to think might be worth while, including some of our members here. It would take someone with influence to spin this into research. I don't know that its worth while to do so. So their it is for what its worth.. lol


Phillip

[NigelP]

I'm struggling to see how a through draft over winter can reduce mites numbers. The cluster temperature will be maintained regardless of whether the bees are in a draft or not.  They will use more stores (energy source) to maintain this temp if the heat loss is whipped away with a through draft. It's one of the things I first notice when I moved to poly hives was the their usage of stores over winter was small compared to uninsulated wooden hives. In our temperate UK climate at least.

[Ben Framed]

I'm struggling to see how a through draft over winter can reduce mites numbers. The cluster temperature will be maintained regardless of whether the bees are in a draft or not.  They will use more stores (energy source) to maintain this temp if the heat loss is whipped away with a through draft. It's one of the things I first notice when I moved to poly hives was the their usage of stores over winter was small compared to uninsulated wooden hives. In our temperate UK climate at least.

Yes the heart of the cluster will maintain a certain warm temperature. As we know the outer bees will slowly work their way to the warmer part of the cluster while the inner cluster bees will slowly work their way out. (Sort of like a living breathing unit) if you wil; Slowly taking turns, trading places. It is the mites attached to these outer bees which will receive the (cold treatment). I have never heard this theory explained by anyone. This is just my out of the box thinking. TheHoneyPump asked about cold treatment once when a number of us were talking about heat treatment methods and products available and my imagination ignited from there. Mr HoneyPump might have hit on something, even though he did not go into detail.

From what I have read, varroa destructor have a softer outer surface than bees 🐝, leaving them exposed and vulnerable to the effects Oxalic Acid Vapor. So therefore could it be reasonable to hope the same weakness (in theory), will leave them vulnerable to the effects of COLD in a similar lethal way as well? While (hopefully) achieving this mite killing effect by the cold wind tunnel inside the hive itself, that you described in your earlier post? And we know that 'Varroa Destructor' comes from a warmer Asian climate.

Though SHB have a hard exoskeleton, even they struggle in the far North in places of Ian Steppler and TheHoneyPump. We are now speaking of a cold treatment to the soft exoskeleton of Varroa Destructor which may be his weakness? Just food for thought.

Phillip

[NigelP]

Interesting idea.
The bees on the outer cluster have to maintain it above 5.5c anything less than they go into a coma.
Be easy to test if chilling bees to say 6c killed the varroa and not the bees.

[The15thMember]

Interesting idea.
The bees on the outer cluster have to maintain it above 5.5c anything less than they go into a coma.
Be easy to test if chilling bees to say 6c killed the varroa and not the bees.

This was going to be my point as well.  This is easily tested, and it would be odd if no one had.  The other thing to remember is that cold-blooded animals, insects, mites, even reptiles are all incapacitated at similar temperatures, because they can't control their body temperature at all.  This makes me doubt whether there would be a manageable difference in the temperatures in order to kill the mites and not the bees.  Not saying it's not possible, but if there was a difference in the lethal low temp, the method of chilling would probably have to be very precise. 

[Ben Framed]

Interesting idea.
The bees on the outer cluster have to maintain it above 5.5c anything less than they go into a coma.
Be easy to test if chilling bees to say 6c killed the varroa and not the bees.

This was going to be my point as well.  This is easily tested, and it would be odd if no one had.  The other thing to remember is that cold-blooded animals, insects, mites, even reptiles are all incapacitated at similar temperatures, because they can't control their body temperature at all.  This makes me doubt whether there would be a manageable difference in the temperatures in order to kill the mites and not the bees.  Not saying it's not possible, but if there was a difference in the lethal low temp, the method of chilling would probably have to be very precise.

Reagan I must respectfully question your fore drawn conclusions. I have searched and have not found any research being done or have been done on this subject, anywhere in the World. As stated earlier, our very own fellow member TheHoneyPump is the first and only person I have EVER heard mention the idea of using cold to fight Varroa Destructor. Not saying it has not been done, but if it has I can not find it. Where you successful in finding paperwork before making your conclusions? If not I will ask further.

Is varroa destructor the same as other mites in make up and physical Characteristics? Do they, coming from a warm Asian atmosphere, have the same protection from cold as other insects? Can 'any mite' you mentioned survive without the protection of a warm blooded host? Or access to warmth in sub freezing temperatures with a wind tunnel of draft effect as in my experiment, as Nigel clearly described my experiment as being? 

Your point of mites being cold blooded is also my point. Most mites live on warm blooded host. Chickens, livestock, wild animals, and birds etc. Varroa is a whole different ballgame. Varroa Destructor does not have this luxury. Are they not totally dependent on their hoist for warmth as well as all other mites? Sure is is true they make it just fine in the confines of a snug as a bug buttoned up hive. Even in Canada, But; If fore mentioned circumstances are in place as described in reply 12 this should most definitely rob them of this 'needed' protection and warmth even when attached to the bees which is on the outside of the cluster.

Without a certain amount of warmth couldn't  they very well perish? Can the also 'cold blooded' bee on the outside of the cluster which is exposed to the frigid sub freezing wind tunnel be able save them? Isn't she subject to the same extreme as the mite? 'Remember she is cold blooded'. That is where the theory rest. The bee, being an insect, is cold blooded as well and her simple cold blooded characteristic can not save the mite on the outside of the cluster where the temperatures are extreme is the theory. Even when attached to the cold blooded bee.

Remember, for many years the 'ENTIRE' scientific community 'as a whole' 'totally' and 'wholly' accepted that varroa lived off of 'bee blood'. It took outside of the box thinking, plus a bold researcher seeking the answers to simple out of the box questions to disprove the accepted myth. Dr Samuel Ramsey. I think it is very possible that cold might very well be an enemy and weakness to Varroa Destructor.

Phillip

[The15thMember]

Reagan I must respectfully question your fore drawn conclusions. I have searched and have not found any research being done or have been done on this subject, anywhere in the World. As stated earlier, our very own fellow member TheHoneyPump is the first and only person I have EVER heard mention the idea of using cold to fight Varroa Destructor. Not saying it has not been done, but if it has I can not find it. Where you successful in finding paperwork before making your conclusions? If not I will ask further.

I know, HP is the only person I've ever heard postulate on this as well, and I'm wondering why that is.  All I meant is that we have bee specialists and acarologists (mite specialists) who are searching for answers to the varroa problem, and it would be strange for none of them to have ever considered cold, especially as heat HAS been considered.  The low temperature at which an organism dies isn't something that needs a paper written on it.  I did search, but couldn't find the answer, but if, for example, the temperature which a mite can survive is the same or lower than a bee, than that would put the idea out the window from the beginning.  I don't know if that is the case or not, I was simply hypothesizing on why cold hasn't been seriously considered until now. 

Is varroa destructor the same as other mites in make up and physical Characteristics? Do they, coming from a warm Asian atmosphere, have the same protection from cold as other insects? Can 'any mite' you mentioned survive without the protection of a warm blooded host? Or access to warmth in sub freezing temperatures with a wind tunnel of draft effect as in my experiment, as Nigel clearly described my experiment as being? 

Your point of mites being cold blooded is also my point. Most mites live on warm blooded host. Chickens, livestock, wild animals, and birds etc. Varroa is a whole different ballgame. Varroa Destructor does not have this luxury. Are they not totally dependent on their hoist for warmth as well as all other mites? Sure is is true they make it just fine in the confines of a snug as a bug buttoned up hive. Even in Canada, But; If fore mentioned circumstances are in place as described in reply 12 this should most definitely rob them of this 'needed' protection and warmth even when attached to the bees which is on the outside of the cluster.

There are thousands of different mites in the animal kingdom.  Some live on warm-blooded creatures, some live on cold-blooded ones.  There are mites that live on other insects, on reptiles, on fish.  Some mites parasitize plants.  There are also many mites that simply live in the soil and have no host at all, as they are not parasitic.  An example is my favorite mite of all, the red velvet mite, a beneficial soil mite which I see all the time around my house. 

Remember, for many years the 'ENTIRE' scientific community 'as a whole' 'totally' and 'wholly' accepted that varroa lived off of 'bee blood'. It took outside of the box thinking, plus a bold researcher seeking the answers to simple out of the box questions to disprove the accepted myth. Dr Samuel Ramsey. I think it is very possible that cold might very well be an enemy and weakness to Varroa Destructor.

Be it far from me to blindly trust science.  For hundreds of years SCIENCE believed the sun revolved around the earth.  My question is simply this: Given that the mites and bees are both cold-blooded, and the bees are only managing their winter temperature through being in an enclosed space with huge numbers of individuals, how would you kill the mites and not kill the bees?  The answer to that question is the answer to this question: What is the lowest temperature a mite can handle, and is it higher than 5.5C/41.9F (the lowest a bee can handle)? 

[Ben Framed]

My question is simply this: Given that the mites and bees are both cold-blooded, and the bees are only managing their winter temperature through being in an enclosed space with huge numbers of individuals, how would you kill the mites and not kill the bees?  The answer to that question is the answer to this question: What is the lowest temperature a mite can handle, and is it higher than 5.5C/41.9F (the lowest a bee can handle)?

Thank you for your deep thoughts on this. My bees handled what was described earlier. "many days not rising above freezing for 'weeks' at a time. The coldest that I recall this winter was 16F . I did not expect this experimental hive to survive" I went on to add in another post of 6 inches of snow on top at one time while they are in an open field. The only real protection the bees had from all of this was that of rain and snow form the lid which was wedged open as pictured and the warmth that they themselves produced in the depth of the cluster. According to Nigels' description, I would think the sides offered  little to no protection from freeze. Also reminding, AR Beekeeper described a survival 'open air' without any protection except the over hang of a bluff, which 'no doubt' handled much lower below freezing temperatures and howling winds than my little hive did. 

One thing which 'may' be overlooked which 'should' be considered if so.
Though both the varroa and the honey bee are both cold blooded, that does not mean they are the same and can survive the same issues. The Honey bee has a protective exoskeleton, while as I understand it the 'varroa' mite does not have this protection luxury. The honey bee survives the elements of OAV while the varroa can't  for lack of exoskeleton protection. This it a sort of similar theory.... except we are talking of using cold instead of OAV....

Adding the SHB which 'does' have a protective exoskeleton and is also cold blooded, apparently has trouble handling the cold of Canada. As reports suggest it does not thrive there.. Different insects have different strengths and weaknesses. Finding those is the key.

Phillip

[The15thMember]

One thing which 'may' be overlooked which 'should' be considered if so.
Though both the varroa and the honey bee are both cold blooded, that does not mean they are the same and can survive the same issues. The Honey bee has a protective exoskeleton, while as I understand it the 'varroa' mite does not have this protection luxury. The honey bee survives the elements of OAV while the varroa can't  for lack of exoskeleton protection. This it a sort of similar theory.... except we are talking of using cold instead of OAV....

I'm sorry that I keep correcting you on things, but varroa has an exoskeleton that is similar to a bee's.  Perhaps not identical, but all arthropods have an exoskeleton made of chitin.  Also from what I've read about OAV, we aren't sure exactly how it acts on mites, which is why it's recommended to rotate it with another kind of treatment, because we are unsure if mites could become resistant to it.

Thank you for your deep thoughts on this. My bees handled what was described earlier. "many days not rising above freezing for 'weeks' at a time. The coldest that I recall this winter was 16F . I did not expect this experimental hive to survive" I went on to add in another post of 6 inches of snow on top at one time while they are in an open field. The only real protection the bees had from all of this was that of rain and snow form the lid which was wedged open as pictured and the warmth that they themselves produced in the depth of the cluster. According to Nigels' description, I would think the sides offered  little to no protection from freeze. Also reminding, AR Beekeeper described a survival 'open air' without any protection except the over hang of a bluff, which 'no doubt' handled much lower below freezing temperatures and howling winds than my little hive did. 

I understand what you are saying, but just because it was 16F outside the hive doesn't mean it was 16F around the cluster.  As Nigel said, the bees maintained the same cluster temperature in the hive with the open lid, they just had to use more energy to do it.  Even an open air hive would have to be able to maintain the winter cluster temperature of around 64F at the core and 44F around the edges to survive.  They could do that in cold temps by shivering, balling, and consuming vast amounts of honey to enable their bodies to keep up these activities. 

Now, if we are discussing this as a mite treatment, first of all the mites would have to die or at least release the bees at a temperature which was still safe for the bees (above 42F).  This treatment would not be usable with brood in the hive, because the brood needs to be between 94F and 96F to develop properly.  If the treatment was used during the winter when the bees are clustered, it would only affect the bees on the outside of the cluster, so it would have to be sustained for long enough to have all the bees cycle to the outside edges.  It would never reach the queen, as she stays in the center of the cluster at all times.  The other question is, how cold would the operator have to make it in the hive for the bees to actually let the temperature drop enough to let the mites release?  Remember that the mites are often wedged between the plates of the honey bees' exoskeletons, so the bees' body temperature would have to be at the mites' critical low temp for them to be affected.  I'm not saying it's impossible, but it seems like a dangerous game.  It would probably be a game of degrees or partial degrees, and it would probably be easy to over-chill the cluster to get the mites.  In the end it depends on whether the mites and bees have significantly different levels of cold tolerance.   

[Ben Framed]

I'm sorry that I keep correcting you on things, but varroa has an exoskeleton that is similar to a bee's.  Perhaps not identical, but all arthropods have an exoskeleton made of chitin.  Also from what I've read about OAV, we aren't sure exactly how it acts on mites, which is why it's recommended to rotate it with another kind of treatment, because we are unsure if mites could become resistant to it.

So far I do not see that you have. lol
No, their exoskeletons are not identical, as that of the bee. Huge Point.  According to Dr Samuel Ramsey OAV attacks the foot of the mite because of its 'softness' which is a weakness as far as OAV and part of the varroas' 'softer' exoskeleton.. 
OAV build up to resistance:
Again I have read just the opposite as this question has supposedly been answered and put to rest by years of research resulting in data from all over the world. Has this changed?

I understand what you are saying, but just because it was 16F outside the hive doesn't mean it was 16F around the cluster.  As Nigel said, the bees maintained the same cluster temperature in the hive with the open lid, they just had to use more energy to do it.  Even an open air hive would have to be able to maintain the winter cluster temperature of around 64F at the core and 44F around the edges to survive.  They could do that in cold temps by shivering, balling, and consuming vast amounts of honey to enable their bodies to generate metabolic heat. 

When temperatures drop to 23?F 'or below', the bees on 'the inside' of the cluster begin 'vibrating their wing muscles' to generate heat, which aids in bringing up the 'internal core' temperature of the cluster. The bees along the outer shell of the cluster 'remain motionless', acting as a 'layer of insulation'. i.e.

I understand clearly your and Nigels' point that the inner cluster will maintain a steady warm temperature. I share that point.
But not the outer limits of that cluster, they do not do that even in a safe buttoned down hive. We are not talking a buttoned down hive but a hive that is exposed to extreme elements of nature.

I see no use in going deeper in the open air hive that was just and good example. But In my case the outside temperature of that cluster inside of the box 'was' 'or near' 16F because of the wind tunneling drafting effect being a steady pull as that of being placed inside a wind tunnel, which no longer offers element and weather protection, nor the ability build to build up warmth in the 'inner space' of the hive because of the gaped open top of hive box and the draft of 'steady' pull from the complete unrestricted opening of bottom. Because of this, unrestrained, below freeing temperatures for weeks at a time are allowed to reach the outer edge of the cluster itself. This can not be denied Physics will not allow. The outer bees 'will' in this senecio, have below freezing air touching their bodies. The air is no longer trapped and siting, as in buttoned down hive set ups.
 
Fresh, New, 'Freezing' air will be a 'steady' flow 'racing' throughout the hive no matter how warm it is below the protective 'insulation bees'. 'Like Rudolph in the blizzard' the bees of the outer edge of the cluster will have freezing air hitting them steady. lol  Will not the mites attached as well?
 
That is the very reason they slowly rotate positions inside the cluster. They can only live so long while siting motionless with 16 degree air hitting them.  And make no mistake, the outer bees of the cluster did deal with it and survive in my experiment just as I am describing now.

I do not know if the attached mites will be able to deal with it. And that question 'is' the point in question. lol
So the same original question, will the freezing air hitting the bees in such a senecio, kill the varroa mites which are attached to the bee when it is their turn to do outer cluster duty? I do not know.

Oh let me add, as far as burning up vast amounts of food or fuel; This hive 'did not' have the added food nor the support of mountain camp on top for extra food. In fact they had no more reserve stores than any of my hives that I 'did' add mountain camp.
 
 
Phillip