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CO2 levels with Indoor Wintering Honeybees

32K views 58 replies 21 participants last post by  wildbranch2007 
#1 ·


I had an interesting brief chat with a neighbour in regards to CO2 levels in his wintering shed. He had bought a CO2 monitoring device and has been monitoring everything from his office to every room in his wintering facility. His main shed is at 950ppm but his other shed is at 3500ppm. The conversation lead to optimal CO2 levels and where that equilibrium is at. 1700ppm seemed to be the common wisdom passed onto us by someone else...

CO2 is an important factor when wintering honeybees. They use it as part of their dormancy control and maintain a certain elevated level of it within their insulating shell, 1700ppm had been suggested.

So in regards to maintaining an indoor wintering rooms c02 levels, high levels might just kill them, trying to maintaining levels comparable to outdoor levels might just be wasted effort.
More importantly however is the wintering room air circulation. Too much air movement within the room can disrupt the hives CO2 sheid and interfere with dormancy. Turn those ceilIng fans down too much and pockets of deadly gasses and air layering will form.

I think it's time I start monitoring CO2 levels and stage my mid winter exhaust fans according to CO2 levels aswell as temp
 
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#4 ·
Somewhere around 40F during the winter time.
Is it possible to connect the fans with the CO2 monitoring device to turn
them on automatically? I wonder if there is such a device exist or any other
method to monitor the CO2 level better.
 
#11 ·
CO2 levels inside the cluster run as high as 60000 ppm and 40000 ppm just outside the cluster. Higher levels of CO2 appear to help bees winter more efficiently and lengthen life spans in winter.

Anecdotally, I feel like the hives getting the most direct blast of air from my intakes do the best making it through winter.
 
#13 ·
I had not heard that overwintering bees kept CO2 levels high and was going to ask if there was research on the subject I could read. I googled it and found this abstract of a small experiment that correlated higher CO2 levels with higher mite mortality. As it is only an abstract I couldn't dig into the nitty-gritty, but I thought it was worth posting nonetheless.
https://www.ncbi.nlm.nih.gov/pubmed/26453704
 
#23 · (Edited)
I had not heard that overwintering bees kept CO2 levels high and was going to ask if there was research on the subject I could read. I googled it and found this abstract of a small experiment that correlated higher CO2 levels with higher mite mortality. As it is only an abstract I couldn't dig into the nitty-gritty, but I thought it was worth posting nonetheless.
https://www.ncbi.nlm.nih.gov/pubmed/26453704
Here are the full papers Adrian & Allen.
1. http://s000.tinyupload.com/index.php?file_id=21204589157812732587
2. http://s000.tinyupload.com/index.php?file_id=60057150347930193285
3. http://s000.tinyupload.com/?file_id=05858068185874882793
 
#14 · (Edited)
Other than Randy Oliver's article the rest are only abstracts as well

http://scientificbeekeeping.com/old-bees-cold-bees-no-bees-part-1/

https://www.researchgate.net/public...gulation_in_honey-bee_Apis_mellifera_colonies

https://www.researchgate.net/public...ance_termination_and_postdiapause_development


I've never been too concerned about CO2 levels in winter. The bees winter in very confined spaces like trees and walls in nature and snowdrifts outside. Far less ventilation than I provide. There may be an optimal level for longevity and sugar consumption that would be good to know. I wouldn't doubt that the optimal CO2 levels for winter are much higher than the levels most people shoot for. Haven't found many studies in this area.
 
#22 ·
There are a couple of issues with this... CO2 does not appear to be lethal to the mites it just anesthetizes them just like the bees. It is a gentle process were the bees fall to lowest point point allowed. Mites still hang on pretty well although some are dislodged. CO2 tends to cause bees to regurgitate their crop contents. A hot mass of sticky bees is a pretty sure disaster, but I guess good mite control too. All depends on your standards.
 
#26 ·
CO2 is good for veggies production inside a grow room. Perhaps you can
figure out a way to harvest some to channel into your grow room for plants and
veggies production during the winter time. Find a way to vent the CO2 into the growing
chamber. Which veggies crops will favor a high to moderate CO2 level?
 
#28 ·
Thanks PV

The Van Nerum and Buelens paper is truly fascinating.

The last point in the discussion "Practical apicultural applications of the findings are not available as yet, but e.g. wintering under artificial hypoxia is no longer an unrealistic prospect." and point 10 "As low airflow for gas analysis is a poor heat transporter, but it is a draught and bees abhor this. It destroys the insulating still-air situation and might hypoxia." makes me wonder if there would be a benefit in leaving entrance reducers on for winter; especially if the ambient RH levels in the wintering room are low and condensation in the hive is not a problem as a result.

I think many of the indoor wintering recommendations as based upon "common sense" but have minimal scientific validity.
 
#30 ·
I've tried wintering with the reducers in place but there was just too much condensation issues inside the hives because of the reduced hive air exchange. Also my hives have no upper entrance so there is no updraft to expel excess humidity.
RH is a tricky balance. Mild weather systems ramp humidity up, then cold dry air systems plumit. I think too dry is better than wet
 
#29 ·
I don't see OAV working in a wintering room either. The OA would sublimate back to solid form before it entered the hive I would think. Repeated doses OA over a period of time would probably result in corrosion any metal and concrete. Formic would work better but would also be extremely corrosive. I can't see either being practical.
 
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