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Setting up for TDSD Study 1st question - Humidity

Discussion in 'Tortoise Breeding' started by Markw84, Dec 17, 2016.

  1. Markw84

    Markw84 Well-Known Member 5 Year Member

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    The "when" is a period of time. And that, in "days", will vary depending upon incubation times. That's why I feel it better to state Stage 16 to Stage 22. That is the bracket of time in which to work. I believe the effects also are cumulative. So many degree-hours above a certain Temperature in that period are required for the proper hormonal environment to achieve the proper estrogen levels. So to me, and my experiments, I see the "when" not as a point in time, but a bracket of time in which I have to apply enough "degree hours" to effect the female outcome.
  2. Will

    Will Well-Known Member

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    This is what is in Kuchling's book. This is a spectacular synopsis. I wish he could have been the author of a few more books.

    Attached Files:

  3. Markw84

    Markw84 Well-Known Member 5 Year Member

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    @Will Love it, and I am ordering the book. Pricey but looks a good addition to my library.

    BUT WE DIGRESS!!

    What is your take on HUMIDITY????????????????
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  4. Will

    Will Well-Known Member

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    So I don't think water vapor will interfere with gas exchange as water vapor are small molecules only ever so slightly bigger than gas molecules. But at the scale of molecules different rules of exchange and barrier crossing occur. If there is dew or droplets of water on the egg shell I think it will reduce gas exchange. I think that can be overcome in a couple of ways, 1) have high air turn over in the incubator, now that does not mean forceful blasting, but even a simple facilitated (passive exchange) by drafting (heated at the bottom with small air holes and slightly larger air hole at the top of the incubator. Or 2) an air stone.

    What troubles me about these ideas is that one incubator I made had no active air exchange and very little passive and most eggs did well. That incubator was an ice chest with several inches of water heated with an aquarium heater. The eggs were placed in moist vermiculite on a shelf above the water. They were not covered in the box that had the vermiculite. I did not monitor RH, just air temp. The water was a big enough heat sink that a daily or every other day look see did not kill the thermal momentum and the incubator would re-achieve the desired air temp very quickly after the lid being opened let all the warm moist air out.

    What I think is that seeing a difference between 80 and 98 % RH might be difficult. With two incubators the empirical result will be easy to notice, that it would stand up to a statistical analysis (and demonstrate a "significant" difference) is another thing.
  5. Will

    Will Well-Known Member

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    Scientists who study this agree and some use "cumulative heat units", Yetems(sp) stages might be a better gauge, but how do you know without sacrificing and egg?

    Entomologists and vineyards managers (among others) use "degree days" to predict insect outbreaks and ripeness of fruit. But again, this does not replace actual observation of the field. So maybe cracking a few eggs along the way would be required.
  6. Markw84

    Markw84 Well-Known Member 5 Year Member

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    At this point I do NOT want to play with humidity to test effects of different levels. I want to pick a RH level, that consensus believes to be optimum, and monitor it only to MAINTAIN it so is does not vary - or at least it is the same for all eggs of the different temperature groups.

    I am currently testing two incubators I constructed from wine coolers as you can see at the top of this post. I have one of the smallest muffin fans blowing across the CHE heat element and across two 4" sq water containers. I use a Helix proportional controller with the probe mounted just an inch or so from the CHE to give a tremendously stable temperature. This gives me 81%RH in the incubator. By using open topped containers for the eggs, I can have the humidity at the egg around 95% if just a tiny bit of moisture is added to the substrate. I am now leaning towards that being the way to go.

    SO... will a 85% RH, stable in the incubator with a small muffin fan running constantly to maintain a more stable temperature and humidity level, dry out the eggs?
  7. Anyfoot

    Anyfoot Well-Known Member

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    Mark. How many different settings could you have? Could you hold 3 different levels of himidity in each incubator.
    So for example
    100%, 80% and 60% at 90f
    100%, 80% and 60% at 80f.
    Last edited: Dec 22, 2016
  8. Markw84

    Markw84 Well-Known Member 5 Year Member

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    @Will One of my very best friends is a large peach farmer. Perhaps that is where I got comfortable talking about temperature hours as we discuss that frequently in assessing the "quality" of the winter.

    I am not interested in looking to definitively establish the temperature sensitive period. I simply want to use that "window" as a way to liberally manage temperature manipulation to mitigate possible scute abnormality with the higher temperatures that should produce more reliable female results. Since we are talking temperature hours, and the theory that it is indeed cumulative, if I can bump the temperatures in the middle of the "estimated" sex sensitive period, I can perhaps use a bit higher temperature than one would use at a constant level throughout the incubation process. I can pretty well estimate the sex setting period based upon know staging for the chelonians extensively tested. It does not need to be exact for my purposes. For example, Red-Ears with a 53 day incubation to pipping, reach stage 17 at day 18. If I extrapolate to a 90 day incubation for my tortoises, that would correspond to day 31. Close enough for my testing.

    Most seem to currently Temperature sex with, for example, a constant temperature of 89f for females. Since I have very accurate temperature monitoring and constant 60 second interval readings, I can test that method. And I can test a constant 88f and 90f. But will I start to see scute deformity? However, what happens if we incubate at 87f for the first 31 days, then bump to 90f or even 91f until day 60, then back to 87f until pipping? My hypothesis is that we will see much more consistant all female outcome, and much less potential for scute deformity as scute delineation would be complete by that stage of development.

    Thoughts??? Anyone??
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  9. Markw84

    Markw84 Well-Known Member 5 Year Member

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    I don't want to test that now. I want to test temperature at different timings as stated above in the post I was making as you posted this. I want to take humidity as a variable out of the equation.
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  10. Anyfoot

    Anyfoot Well-Known Member

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    I understand, my thought process was this, and the more info you get before you proceed the better.
    If in the wild there are 2 nests, one at 80f and one at 90f. I would have thought after a period of time the 90f temperature nest was lower in humidity as it dries out faster, If we as keepers when incubating at higher temps to force female dominance also inadvertently have a high humidity (90/100% at the egg), does it cause scute deformity.
  11. Markw84

    Markw84 Well-Known Member 5 Year Member

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    That is a different experiment, but interesting. However, I don't think in the closed environment of a natural nest chamber, the humidity would go down. I would conjecture that if a nests dries out, the eggs die. If the earth remains moist - you will have pretty much 100%RH whatever the temperature with that small of a closed chamber. I sure wish we could find results with a sensor placed in real nests. No one seems to record, or track humidity at all that I've seen.
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  12. Anyfoot

    Anyfoot Well-Known Member

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    Maybe that is what we are missing.
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  13. Markw84

    Markw84 Well-Known Member 5 Year Member

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    I have been reminded to reply to this question. Sorry I have seemed to have forgotten about it, so thanks for the reminder....

    I have started using the SensorPush. It is a small square sensor I can place anywhere and it records and logs both temperature and humidity. It downloads automatically to my iPhone any time I am within Bluetooth range. If I am not in range for an extended period of time, it will store data for up to 20 days. The data can be saved as a CSV file for import into excel for conversion to a graph. This way I can create a graph of the exact temperature and humidity over the course of an entire incubation period, for example. I will know exactly the temperature hours any egg was subjected to and at what timing. The sensor is about 1 1/2 inch square and 1/2 inch thick. Easily fitting inside an egg container right along with the eggs.

    I also have them in my closed chambers and can see the temperature swings and humidity swings that naturally occur throughout the day. Just this morning we had a rare power outage here due to construction nearby. I like being able to look back and see what that did to the enclosures over the period of that outage in the wee hours of the morning when I was unaware.

    I have 8 of them currently, All 8 are synced to the app on the iPhone, so no problem with the mixing of too many signals of the same frequency you get if you use too many of the wireless, less expensive digital thermometers. As far as I know, there is no limit to the number of sensors you can sync to one app.

    I also check accuracy best I could with salt tests and freezing water tests. I then placed all 8 sensors side by side for the day. All 8 read within 0.1 degrees F of each other. All 8 read within 0.2% RH of each other. There is also a setting feature in the app where you can adjust the temp and humidity reading up or down to calibrate if necessary, but I have found it unnecessary so far.

    They are a bit pricy, at $50 ea. but not bad for the accuracy and logging feature I was after. I feel well worth it.

    Sensorpush.jpg
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  14. Sterant

    Sterant New Member

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    I also use the SensorPush products. Work great!
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  15. Markw84

    Markw84 Well-Known Member 5 Year Member

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    Dan

    Any other thoughts about this thread and humidity in the egg container / incubator???
  16. Sterant

    Sterant New Member

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    I use still-air Hovabators and have for 20 years. Talking specifically about Leopard and Star tortoises (I have never incubated turtle eggs). I have never added any water to the vermiculite. I put the eggs in individual tupperware containers with loose fitting tops (I don't snap them shut) in totally dry vermiculite. Inside the incubator but outside of the tupperware containers, I put a couple small trays full of water with a sponge sitting in them. I have always had success doing it this way so never played around too much. I generally add water to the trays weekly. I don't have anything in the incubator right now but the next time I do, I will put a SensorPush in the container with the eggs and see what reading I get. Between adding water to the trays, inspecting the eggs and checking temps with the temp gun, I generally have the incubator open twice a week for less than a minute.
  17. Markw84

    Markw84 Well-Known Member 5 Year Member

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    Thanks you so much, Dan. I am hearing more and more people are tending to go totally dry substrate with diapause species. When I set up my incubator this way, with the water trays, the humidity stays in the low 80's. I do have larger incubators with 5 - 6 shelves for eggs, so also use a very small muffin fan on continuously. That is blowing across the heat element and over the water tray. That does help keep the humidity stable and up at 80+
    @Dan Sterantino do you have any star tortoise eggs yet this year? Isn't this their time to lay?
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  18. Sterant

    Sterant New Member

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    Nope. Sold off all of my stars and leopards a number of years ago. 100% focused on radiated tortoises now.
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  19. KevinGG

    KevinGG Well-Known Member

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    Just bought 4. Thanks for the recommendation.
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  20. mark1

    mark1 Well-Known Member

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    https://webcache.googleusercontent.com/search?q=cache:8zsxOWWa8ZgJ:https://www.clarkson.edu/honors/research/summer_papers/Davis-Andrew%20Abstract.doc+&cd=1&hl=en&ct=clnk&gl=ushttps://webcache.googleusercontent.com/search?q=cache:8zsxOWWa8ZgJ:https://www.clarkson.edu/honors/research/summer_papers/Davis-Andrew%20Abstract.doc+&cd=1&hl=en&ct=clnk&gl=us


    "The humidity of the nest is another environmental influence that can alter the physical traits of the hatchlings. The shell of a turtle egg is semi-permeable and therefore allows water to move through it. When the egg is in a more humid environment, it absorbs a large amount of water from the surrounding soil. However, in a drier nest, the egg will not absorb as much water and may even lose some of its mass. This means the eggs in the moist nests will be have more mass and will yield larger hatchlings (Packard et al. 1991), which have a higher probability of living to sexual maturity (Cagle et al. 1993). The eggs from a more humid nest also have a longer incubation time then the eggs from a drier nest (Packard et al. 1991). The humidity of the nest does not, however, have any influence on the gender distribution of the hatchlings (Packard et al. 1991)."
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