Derek Mitchell article discussing effect of higher humidity on varroa
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  1. #1
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    Default Derek Mitchell article discussing effect of higher humidity on varroa

    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/d...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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  3. #2
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    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by clong View Post
    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/d...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."
    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
    Former "smoker boy". Classic, square 12 frame Dadants >> Long hive/Short frame/chemical-free experimentations.

  4. #3
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    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by GregV View Post
    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?

  5. #4
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    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by Litsinger View Post
    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-Rubb...01201172&psc=1
    Former "smoker boy". Classic, square 12 frame Dadants >> Long hive/Short frame/chemical-free experimentations.

  6. #5
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    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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
    Former "smoker boy". Classic, square 12 frame Dadants >> Long hive/Short frame/chemical-free experimentations.

  7. #6
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    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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.
    Former "smoker boy". Classic, square 12 frame Dadants >> Long hive/Short frame/chemical-free experimentations.

  8. #7
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    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by GregV View Post
    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

  9. #8
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    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by Litsinger View Post
    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.

  10. #9
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    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by clong View Post
    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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