Derek Mitchell article discussing effect of higher humidity on varroa - Page 2
Page 2 of 2 FirstFirst 12
Results 21 to 33 of 33
  1. #21
    Join Date
    Mar 2015
    Location
    Decorah, Iowa USA
    Posts
    245

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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

  2. Remove Advertisements
    BeeSource.com
    Advertisements
     

  3. #22
    Join Date
    Apr 2015
    Location
    Richmond, VA, USA
    Posts
    369

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by Swarmhunter View Post
    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.

  4. #23
    Join Date
    Oct 2019
    Location
    Wakefield, Rhode Island, USA
    Posts
    288

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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.

  5. #24
    Join Date
    Oct 2019
    Location
    Wakefield, Rhode Island, USA
    Posts
    288

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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).

  6. #25
    Join Date
    Oct 2019
    Location
    Wakefield, Rhode Island, USA
    Posts
    288

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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.

  7. #26
    Join Date
    Apr 2015
    Location
    Richmond, VA, USA
    Posts
    369

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by Robert Holcombe View Post
    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?

  8. #27
    Join Date
    Oct 2019
    Location
    Wakefield, Rhode Island, USA
    Posts
    288

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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.

  9. #28
    Join Date
    Apr 2015
    Location
    Richmond, VA, USA
    Posts
    369

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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.

  10. #29
    Join Date
    Oct 2019
    Location
    Wakefield, Rhode Island, USA
    Posts
    288

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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.

  11. #30
    Join Date
    Mar 2015
    Location
    Decorah, Iowa USA
    Posts
    245

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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

  12. #31
    Join Date
    Oct 2019
    Location
    Wakefield, Rhode Island, USA
    Posts
    288

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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!?

  13. #32
    Join Date
    Mar 2015
    Location
    Decorah, Iowa USA
    Posts
    245

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    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

  14. #33
    Join Date
    Jun 2018
    Location
    Boaz, KY, USA
    Posts
    1,676

    Default Re: Derek Mitchell article discussing effect of higher humidity on varroa

    Quote Originally Posted by Litsinger View Post
    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.

    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?).

    Upper Entrance.jpg
    Ecclesiastes 11:4

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •