Why measure UVB to manage Vitd3 p.synthesis ?

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Claudiusx

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Aaradimian":jngr911x said:
To KN's point about the equivalence (or lack there of), of human vs lizard skin, I completely agree. As seen in that article I posed about mold, biological systems are all over the map in terms of tolerance to various things.

I agree that they can be different. How much different we don't know. However, another point i've made multiple times that doesn't want to be discussed apparently is genetic skin mutations, such as hypos, trans, leatherbacks, and silkies.

Obviously we know with silkies that they need extremely special care in regards to lighting. It is a foolish assumption that captive bred hypos/trans/leathers can tolerate the same uv levels as their wild counterparts, who usually are much darker, and with much thicker and spikey-er skin.

My whole problem with this whole uvb debate is that some people think that the stronger the better, that if you don't have the strongest bulb with a reflector and it be under the screen, that you're not doing it right. That you need to recreate natural UVI levels.

Basing what you provide for 12-15 hours of the day on 1 hour of the most extreme wild UVI is also foolish. Now, if you were to be able to have multiple uvb bulbs, and wanted to provide that type of uvi for an hour or so at noon time to replicate their natural environment, that would be a lot different than forcing them to be under that uvi level for the whole entire day.

-Brandon
 

Aaradimian

Juvie Member
claudiusx":174p4vmw said:
I agree that they can be different. How much different we don't know. However, another point i've made multiple times that doesn't want to be discussed apparently is genetic skin mutations, such as hypos, trans, leatherbacks, and silkies.

Obviously we know with silkies that they need extremely special care in regards to lighting. It is a foolish assumption that captive bred hypos/trans/leathers can tolerate the same uv levels as their wild counterparts, who usually are much darker, and with much thicker and spikey-er skin.

My whole problem with this whole uvb debate is that some people think that the stronger the better, that if you don't have the strongest bulb with a reflector and it be under the screen, that you're not doing it right. That you need to recreate natural UVI levels.

Basing what you provide for 12-15 hours of the day on 1 hour of the most extreme wild UVI is also foolish. Now, if you were to be able to have multiple uvb bulbs, and wanted to provide that type of uvi for an hour or so at noon time to replicate their natural environment, that would be a lot different than forcing them to be under that uvi level for the whole entire day.

There's certainly a validity to investigating the differences in morphs since it directly involves their skin. What percentage of the change is cosmetic from a UV standpoint? Do the same genes that code for spikes also help provide DNA protection from UVA? Questions like that. As we see from sad situations such as hip problems in black lab retrievers and breathing issues with bulldogs, selective breeding over generations can have a dark side.

In the absence of evidence one way or another, my initial feeling about varying UV over the course of a day is similar to yours. With my two, I have areas where they can escape the UV entirely, and varying heights under it so they can choose their exposure level. Unlike visible light bulbs, you have to maintain the temperature of the plasma to put out the correct wavelengths of UV, so a dimmer isn't an option (as far as I'm aware), so this is my "next best guess" at trying to provide a suitable environment for mine.

At a base level, I suspect that they "know" how much they're supposed to get, similar to them "knowing" how/when to brumate, and for how long. Again, without anything solid to go on, it's trial and error. I have already erred once with UV by providing too little per the guidelines on the Arcadia bulb I have as a result of underestimating the fall off in irradiance with distance (still much to learn about beardies!). I can only hope that I'm providing them with a happy, healthy home, but the scientist in me would feel a lot better with some research data to back up my observations on their well-being.
 

Claudiusx

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Aaradimian":102aucli said:
n the absence of evidence one way or another, my initial feeling about varying UV over the course of a day is similar to yours. With my two, I have areas where they can escape the UV entirely, and varying heights under it so they can choose their exposure level. Unlike visible light bulbs, you have to maintain the temperature of the plasma to put out the correct wavelengths of UV, so a dimmer isn't an option (as far as I'm aware), so this is my "next best guess" at trying to provide a suitable environment for mine.
In another thread a member had mentioned an idea that is an interesting concept. Having an array of multiple uvb bulbs. Weaker, strong, stronger. And varying the time at which they come on. Since you can't dim them, this is the only real feasible way to very the uv throughout the day. So, for instance you would have your weak one come in in the morning, stronger one a few hours later, strongest at around noon, then the strong one a bit after that, finally followed by the weak one until night time. Or even cutting uv completely for the last hour or two.

It's an interesting idea. I don't think we need to go that far with our dragons, I just don't think we need to be exposing them to as much as is being suggested by some. It would be different if UV radiation didn't have any negative side effects, but the facts are that it does. And I really believe that is something that gets lost on a lot of people.

-Brandon
 

Claudiusx

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Aaradimian":2p6f57x8 said:
There's certainly a validity to investigating the differences in morphs since it directly involves their skin. What percentage of the change is cosmetic from a UV standpoint? Do the same genes that code for spikes also help provide DNA protection from UVA? Questions like that.

Now that I think of it, an easy test (although morbid and not 100% accurate most likely as it would be done on deceased dragons) would be to simply place the skin from these different morphs in front of UVI meters, and see the difference in the amount of UV radiation that is transmitted through the skin. From there, if we could even get a percentage difference, that percentage difference could be applied to how we sestup our tanks for these morphs.

For instance, if on average a trans dragons skin allows 50% more UV radiation to penetrate than a normal morph, we could pretty safely assume that we could cut our recommendation in half as far as uv goes for Trans dragons.

This is a much easier test to do than measuring blood levels under varying UVI levels, like mentioned in my other thread here: https://www.beardeddragon.org/forums/viewtopic.php?f=6&t=249953

All hypothetical and theory of course, but this is what I love about starting discussions, ideas and thoughts come up when people are actually willing to discuss.

-Brandon
 

Aaradimian

Juvie Member
In another thread a member had mentioned an idea that is an interesting concept. Having an array of multiple uvb bulbs. Weaker, strong, stronger. And varying the time at which they come on.

That is interesting, if expensive. One of my issues is that we dispense advice about bulbs here to people who are just barely able to maintain the basics of care because of money issues. One thing that might be worth looking at is selecting a tube that appears (based on the experience of people who have raised beardies for a long time), to be good for them. We then use some good measuring gear and chart out the UV strength at different heights. I know that vendors provide this, but it'd be good to double check their numbers.

From my own experience, I was shocked by the fall-off in intensity with distance, but this could actually be an advantage. We could then advise sloping the tube in the viv, or maybe advocate a stepped tier decoration where they could bask at different "altitudes" as they choose. That way, they could get a range of UV intensities, or be out of it completely? I know KN has some good kit & knowledge about measuring techniques from other threads. Do you guys think this merits investigation? I certainly don't have the time, talent, or inclination to undertake a rigorous study of the biological effects of UV on different beardie morphs, or to dig into the literature to find if someone else has, but I do think that it could potentially improve the lives of our little friends- which is why were here, right?
 

CooperDragon

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It's certainly good to create different basking zones to provide plenty of options for them. In addition to levels you can move the UVB light forward or backward in the tank to create a gradient along the width of the tank. I've done testing on several common bulbs and have results I can send to you if you'd like.
 

Aaradimian

Juvie Member
CooperDragon":2t3395wv said:
It's certainly good to create different basking zones to provide plenty of options for them. In addition to levels you can move the UVB light forward or backward in the tank to create a gradient along the width of the tank. I've done testing on several common bulbs and have results I can send to you if you'd like.

That would be good data to start with. If some other posters have done something similar, it'd be interesting to see how well the data tracks between observers. We're not all going to have the same gear, so it's not rigorous, but it might be informative nonetheless.
 

kingofnobbys

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Aaradimian":20pg4qkr said:
claudiusx":20pg4qkr said:
I agree that they can be different. How much different we don't know. However, another point i've made multiple times that doesn't want to be discussed apparently is genetic skin mutations, such as hypos, trans, leatherbacks, and silkies.

Obviously we know with silkies that they need extremely special care in regards to lighting. It is a foolish assumption that captive bred hypos/trans/leathers can tolerate the same uv levels as their wild counterparts, who usually are much darker, and with much thicker and spikey-er skin.

My whole problem with this whole uvb debate is that some people think that the stronger the better, that if you don't have the strongest bulb with a reflector and it be under the screen, that you're not doing it right. That you need to recreate natural UVI levels.

Basing what you provide for 12-15 hours of the day on 1 hour of the most extreme wild UVI is also foolish. Now, if you were to be able to have multiple uvb bulbs, and wanted to provide that type of uvi for an hour or so at noon time to replicate their natural environment, that would be a lot different than forcing them to be under that uvi level for the whole entire day.

There's certainly a validity to investigating the differences in morphs since it directly involves their skin. What percentage of the change is cosmetic from a UV standpoint? Do the same genes that code for spikes also help provide DNA protection from UVA? Questions like that. As we see from sad situations such as hip problems in black lab retrievers and breathing issues with bulldogs, selective breeding over generations can have a dark side.
<<< People who tinker with the genetics to produce dragons who have unnatural skin malformations are NOT doing their animals any favours.This has more to do with producing "designer" dragons who can attract a much higher price and human vanity than good p.vitticept husbandry.

In the absence of evidence one way or another, my initial feeling about varying UV over the course of a day is similar to yours. With my two, I have areas where they can escape the UV entirely, and varying heights under it so they can choose their exposure level. Unlike visible light bulbs, you have to maintain the temperature of the plasma to put out the correct wavelengths of UV, so a dimmer isn't an option (as far as I'm aware), so this is my "next best guess" at trying to provide a suitable environment for mine.

At a base level, I suspect that they "know" how much they're supposed to get,

<<< yes this is my direct personal observation for wild skinks , snakes , dragons and crocodiles in their natural ranges , they DO INDEED bask for short periods through out the day to
>> thermoregulate
>> to take their requirements of BOTH UVA & UVB and p.synthesis VitD3 in their skin, this UV irradiation is not done ALL IN ONE HIT , unlike with tame captive pet reptiles who will take longer to absorb enough UV to meet their biological needs than wild reptiles will as a consequence of the much lower UVA & UVB flux available to them in their tanks.


similar to them "knowing" how/when to brumate, and for how long. Again, without anything solid to go on, it's trial and error. I have already erred once with UV by providing too little per the guidelines on the Arcadia bulb I have as a result of underestimating the fall off in irradiance with distance (still much to learn about beardies!). I can only hope that I'm providing them with a happy, healthy home, but the scientist in me would feel a lot better with some research data to back up my observations on their well-being.

Some interesting science regarding reptilian skin c/f mammalian skin
>>> Adaptation to the Land: The Skin of Reptiles in Comparison to That of Amphibians and Endotherm Amniotes , L. Alibardi
ref Journal of Experimental Zoology Part B Molecular and Developmental Evolution 298(1):12-41 · August 2003 
>>> Reptile scale paradigm: Evo-Devo, pattern formation and regeneration , Cheng.C, Ping.W, R.E. Baker,P.K. Maini, L.Alibardi, and Cheng-Ming.C.
ref Int J Dev Biol. 2009; 53(5-6): 813–826.

Even the most cursory scan of these scientific papers in peer reviewed scientific journals will show there is CONSIDERABLE differences between reptilian skin & mammalian skin ( and human skin ) and the response to UV is significantly different.

Sorry Brandon but hidden message boards don't cut the mustard as far as being a legitimate form of "evidence" , as those of us who have no access to the "hidden forum" have no way of checking the posts "copied" or the context of the comments claimed to have been made by "notables / experts" therein. You could just as easily created the post you claim to have received from chosen "expert" (Francis).
Furthermore : as far as I am aware , Francis has never actually claimed to visited visited Australia or spent any time in the Australian summer in the natural range of p.vitticepts or another other season in Australia to ACTUALLY observe the activity / behaviors of wild p.vitticepts. (Very few foreigners go to the outback or tropical north in summer (too hot for them)), they all go in the cooler tourist season (April to September), even then a coach load of tourists will rarely encounter shy reptile, whereas a small quiet family group like mine who are camping (in often very remote 4x4 access only locations like we did , regularly encountered wild reptile who rarely saw humans were more curious about us than scared of us ).

I live in Australia and have spend long years living & working in their natural range. Is my personal first hand observation that p.vitticepts do not disappear at noon UNLESS the temperature is above their normal activity temperature range and exceeds their voluntary maximum temperature of 41 degC.
p.vitticepts can frequently be observed basking and foraging through out the entire day even in summer in their natural range and their activity is more governed by the temperature than the UV flux (which they have evolved to tolerate even at extreme UV-Index (high UVB flux as high as about 0.5 mW UVB / sq.cm).
While there are heatwaves in summer in the natural range of p.vitticepts, these conditions don't last for the entire season or even most of it's duration and there are extended periods when it's very overcast while warm/hot.
More real data
decsolstfairweather-800px.gif

ref from http://www.uvguide.co.uk/uvinnature.htm .

I have never recommended higher UVB flux than 200 microW UVB/sq.cm (equiv UV-Index about 7) , Arcadia Reptile this maximum UVB flux for p.vitticepts as well.
 

Claudiusx

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You realize you're discrediting her and using her website as reference all in the same post?

Its clear you pick and choose what charts to show and which parts of information you share as long as it agrees with you.
Such as a chart of uW uvb during a solstice.... also known as the day the sun is closest to the earth..... also known as the day when uv radiation will be the highest of the year.... also known as, not a good example of average uv levels for the year.

I do love how you only argue points I make if you can find a magical little chart for it lol. As at one point you say the points I make aren't worth discussing to you. but the second I bring up something that relates to one of your beautiful charts that you can Google, you're all for it lol. Why cant you just discuss something with your own words instead? I think I know the answer to that one so I'm gonna go ahead and leave this thread, as it's clear your intent isnt to have a meaningful discussion, it's to demand that everyone concedes and admit you're right. Which is evident by hiding from certain valid discussion points.
When you actually want to have a discussion instead of an ego show of charts to make yourself look knowledgeable (when you dont have your own words to back it up) you can come to the other thread, as at this point, we aren't even on topic of your original post.

-Brandon
 

Claudiusx

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Oh and last point, in the link you referenced to her site, she even states this right above the chart you decided to post. Like I said, you pick and choose only what agrees with you.

When considering UVB in nature it is very important to remember that NO reptiles sit out in the sun all day. It is easiest to record maximum levels of solar UVB out in the open, under a clear sky. It is valid to gather such data since this gives a clear indication of the maximum UVB that a basking reptile could receive. It is far from valid, even dangerous, then to suggest that these levels should be provided in the vivarium. Account must be taken of the microhabitat, for every species. What shade and shelter does a wild reptile have? Does it ever see full sunlight? We are hoping to collect data from reptile microhabitats as well as readings taken under an open sky on clear days... but both types of recording are necessary.
 

kingofnobbys

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CooperDragon":37ep0qj0 said:
It's certainly good to create different basking zones to provide plenty of options for them. In addition to levels you can move the UVB light forward or backward in the tank to create a gradient along the width of the tank. I've done testing on several common bulbs and have results I can send to you if you'd like.

This is why it's good practice to allow areas of high UV, moderate UV and low to zero UV, the dragon will choose the area it needs to be in to receive it's required irradiation dosage of UVA flux and UVB flux.
That is to provide a UV gradient in the tank for the dragon to move through much as they do when they thermoregulate.
 

kingofnobbys

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claudiusx":f1jtegj8 said:
Oh and last point, in the link you referenced to her site, she even states this right above the chart you decided to post. Like I said, you pick and choose only what agrees with you.

When considering UVB in nature it is very important to remember that NO reptiles sit out in the sun all day.
<<< blanket statements like that are clearly inaccurate for many species of reptiles , anyone who has seen how wild reptiles behave in their native ranges will know that.

It is easiest to record maximum levels of solar UVB out in the open, under a clear sky. It is valid to gather such data since this gives a clear indication of the maximum UVB that a basking reptile could receive. It is far from valid, even dangerous, then to suggest that these levels should be provided in the vivarium. Account must be taken of the microhabitat, for every species. What shade and shelter does a wild reptile have? Does it ever see full sunlight? We are hoping to collect data from reptile microhabitats as well as readings taken under an open sky on clear days... but both types of recording are necessary.
 

Claudiusx

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kingofnobbys":83gkvost said:
claudiusx":83gkvost said:
Oh and last point, in the link you referenced to her site, she even states this right above the chart you decided to post. Like I said, you pick and choose only what agrees with you.

When considering UVB in nature it is very important to remember that NO reptiles sit out in the sun all day.
<<< blanket statements like that are clearly inaccurate for many species of reptiles , anyone who has seen how wild reptiles behave in their native ranges will know that.

It is easiest to record maximum levels of solar UVB out in the open, under a clear sky. It is valid to gather such data since this gives a clear indication of the maximum UVB that a basking reptile could receive. It is far from valid, even dangerous, then to suggest that these levels should be provided in the vivarium. Account must be taken of the microhabitat, for every species. What shade and shelter does a wild reptile have? Does it ever see full sunlight? We are hoping to collect data from reptile microhabitats as well as readings taken under an open sky on clear days... but both types of recording are necessary.

Oh boy lol.... so you're saying her statement that reptiles dont spend their whole waking hours out in the sun is false? So you're saying that bearded dragons do in fact spend their whole entire time out in full sun?....... Haha.

Umm... got any comments for the other points she makes in that paragraph? Lol. Namely the part about far from valid, dangerous?

-Brandon
 

kingofnobbys

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claudiusx":3r6iqado said:
You realize you're discrediting her and using her website as reference all in the same post?

<<< nothing wrong with the irradiance data shown on her site.

<<< I disagree with her assumptions that reptilian (p.vitticepts) skin UV response is similar to human skin UV response , this is not supported by any hard testable scientific data or evidence and a dangerous assumption to bandy about.
Vague notions about "microclimates" are worthless unless you tie them down with physical measured/measurable conditions and constraints based - just so much handwavy nebulous bulldust otherwise.

I have conducted a thorough metasearch and found nothing that supports this assumption in any peer reviewed scientific literature (using the online literature search facilities available to me as an ex-academic / researcher at the Uni of Newcastle's library).
Is very clear that the structure of reptilian skin is very different to mammalian skin for starters and has evolved to tolerate extreme levels of UV irradiance.

The amount of UV transmitted through p.vitticepts scales should be a relatively easy part the reptilian skin structure to measure, perhaps some undergraduate science student can do a study in the UV transmission through various types of scales found on common morphs of p.vitticepts and other common pet reptiles as a final year or honour year research project.
If there is a student here, I'll help them come up with the measurement procedure and recommend an appropriate UV-Vis scanning spectrometer to use , and help guide their data analysis , they wont be the first research student I've assisted , mentored or supervised.


>>> It's you that has very poor credibility , not Francis. I don't see anything other than handwaving from you , and clearly no science to support your opinion.
When you find some peer reviewed science that supports your opinions ( I wont give them the status of being a hypothesis ) feel free to post it for us more scientifically trained and literate folk to review .



Its clear you pick and choose what charts to show and which parts of information you share as long as it agrees with you.
Such as a chart of uW uvb during a solstice.... also known as the day the sun is closest to the earth..... also known as the day when uv radiation will be the highest of the year.... also known as, not a good example of average uv levels for the year.
<<<< The sun is indeed closer to the earth in the Australian summer & southern summer solstice due to the elliptical orbit of the earth , and the axis tilt of the earth too, and the geographic location of the Australian mainland (straddling the Topic of Capricorn fairly equally, whereas ConUSA is north of the Tropic of Cancer) , hence higher solar irradiance and higher UV-Indexes here in summer than in the north American summer . This is what p.vitticepts have evolved to cope with over 10s of millions of years. Get over it.

I do love how you only argue points I make if you can find a magical little chart for it lol. As at one point you say the points I make aren't worth discussing to you. but the second I bring up something that relates to one of your beautiful charts that you can Google, you're all for it lol. Why cant you just discuss something with your own words instead? I think I know the answer to that one so I'm gonna go ahead and leave this thread, as it's clear your intent isnt to have a meaningful discussion, it's to demand that everyone concedes and admit you're right. Which is evident by hiding from certain valid discussion points.
When you actually want to have a discussion instead of an ego show of charts to make yourself look knowledgeable (when you dont have your own words to back it up) you can come to the other thread, as at this point, we aren't even on topic of your original post.

-Brandon
 

Claudiusx

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Im not talking about summer in Australia vs the us, I'm talking about you using a chart of uv levels during a SOLSTICE. Do you not read the charts you post? Do you not understand what a solstice is? Or do you purposely post misleading charts and hope no one will notice. Saying 200 uW is acceptable because a chart during a SOLSTICE shows levels in the 400 is extremely ill founded.

And you can go ahead and read Francis' articles yourself. Unlike you, my ego doesn't dictate that everyone think im smart or know it all. I care about false dangerous information and suggestions being spread, and dont care who has to be listened to for that to stop.
So if I don't fit your criteria of credible (idk how I'll sleep tonight now that I know you think that of me) then open up your mind, leave your ego at the door, and go read Francis' work. Although its clear if you don't agree with it, its wrong. But just try huh, you can do it.

-Brandon
 
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