# Light Cycles



## Nicholas (Mar 16, 2010)

Hello!

I got a question about light cycles. Yes i know the frogs don't really need the light, the ambient light from the window is enough. But the plants need the light and the frogs also need to sleep.

So, what would be the optimum light cycle for the plants to sustain healthy growth, and for the frogs to get a good nights rest before there next big day ?

12/12 ?
18/6 ?
6/18 ?
10/14 ?
14/10 ?

How much dark time does a frog need? I am sure they can benefit from a natural light cycle...

i got 2 lights, both set on separate timers, one clicks on then an hour later the other turns on, same as at night time one clicks off then an hour later the other one does. i thought that might be a good idea since i am running 2 lights anyhow and it would help simulate a more natural light cycle...

and it got me wondering how long of a dark or night cycle would the frogs benefit from the most. right now they are on a 14 on 10 off cycle...

anyone with knowledge on this subject care to elaborate here?


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## Occidentalis (Jul 11, 2009)

Having done some work in a circadian lab and as a member of SRBR, I can tell you that while there hasn't been much work on frogs, or darts in particular, it seems that among most animals, 12:12 is sufficient. Light cycles don't fluctuate very wildly near the equator. 

They only thing is making sure it's as dark as possible. All animals do better in total darkness - blue LED lights are the worst, but even star light can disrupt circadian rhythms. 

With everything, I run more on than off just for viewing purposes.


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## wimvanvelzen (Nov 1, 2008)

Occidentalis, have you got a link or something about the blue leds? They seem quite popular, so evidence against using them would be very interesting!

And would there be any way to mimick the moon cycles of nature?


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## Occidentalis (Jul 11, 2009)

http://www.annals.edu.sg/pdf/37VolNo8Aug2008/V37N8p669.pdf

While this isn't the article I was looking for initially, it gives a good overview of things. It's focused more on kicking things back on track, but you can imagine how sensitive blue light receptors (which are said to have evolved in the ocean, how cool is that?) in a properly entrained person could respond to the same signals and cause disruption. 

I'll work on finding the one that deals with disruption. The cat just took a bite out of one of the Easter desserts on the table though, so it might be a little while.


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## koldshot (Jan 21, 2010)

wimvanvelzen said:


> And would there be any way to mimick the moon cycles of nature?


Digital Aquatics

Note the MLC module below.

I would speculate as well though, due to darts natural habitat, they would do best in total darkness.


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## jeeperrs (Jan 14, 2010)

Now, we would have to assume that frog eyes have the same ganglion cells and that those cells have the same reaction to blue light. Also, does anyone know about frogs production of melatonin? 
I don't know anything about frogs' brains but I don't think they are very similar to the human brain. These would be things we would have to think through before making generalizations that our human experience is the same as a frogs experience. However, it was a fun read.


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## Occidentalis (Jul 11, 2009)

jeeperrs said:


> Now, we would have to assume that frog eyes have the same ganglion cells and that those cells have the same reaction to blue light. Also, does anyone know about frogs production of melatonin?
> I don't know anything about frogs' brains but I don't think they are very similar to the human brain. These would be things we would have to think through before making generalizations that our human experience is the same as a frogs experience. However, it was a fun read.



It has nothing to do with higher level functioning. Basic circadian rhythms, pineal function, and SCN function are highly conserved across the animal kingdom. 

These processes aren't just in the brain, but in cells themselves. Most of what we know has come from drosophila.


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## jeeperrs (Jan 14, 2010)

Occidentalis said:


> It has nothing to do with higher level functioning. Basic circadian rhythms, pineal function, and SCN function are highly conserved across the animal kingdom.
> 
> These processes aren't just in the brain, but in cells themselves. Most of what we know has come from drosophila.


I am not saying it has to do with higher level functioning. However, you are talking about a very complex system that creates the circadian rhythm. You are right, the process isn't in just the brain, which is why melatonin is a hormone and not a neural pathway. I agree that 12/12 is plenty of light and that is what I run. But since you are a researcher, I would think we could both agree that substantial generalizations from one species to the next can be problematic. Would you say the blue LEDs are bad for fish? I just ask for someone who knows both neural and hormonal responses in frogs to step and share what they know. Then we, or at least I, can take this research as more fact than I can at the moment (relating it to frogs). Just so you know, the read was good enough that if I had blue LEDs in my frogs, I would consider taking them out. So I am not discrediting you but asking more questions.


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## Nicholas (Mar 16, 2010)

this is getting interesting... it would only make since that day/night/lunar cycles could effect our frogs...

that link you left up there for some reason dont work for me... what do they talk about ?


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## Occidentalis (Jul 11, 2009)

jeeperrs said:


> I am not saying it has to do with higher level functioning. However, you are talking about a very complex system that creates the circadian rhythm. You are right, the process isn't in just the brain, which is why melatonin is a hormone and not a neural pathway. I agree that 12/12 is plenty of light and that is what I run. But since you are a researcher, I would think we could both agree that substantial generalizations from one species to the next can be problematic. Would you say the blue LEDs are bad for fish? I just ask for someone who knows both neural and hormonal responses in frogs to step and share what they know. Then we, or at least I, can take this research as more fact than I can at the moment (relating it to frogs). Just so you know, the read was good enough that if I had blue LEDs in my frogs, I would consider taking them out. So I am not discrediting you but asking more questions.



Generalization can be problematic, but in this case I don't find it to be. Melatonin and circadian function seems to be a basal characteristic in most animals. Across the vertebrates, things are very similar. Circadian rhythms in a nutshell -- EDERY 3 (2): 59 -- Physiological Genomics

I would say blue LED's are bad for fish - they seem to disrupt rhythms across every clade. See Suppressing Drosophila Circadian Rhythm with Dim Light -- Winfree 183 (4128): 970 -- Science and Some Perturbations That Disturb the Circadian Melatonin Rhythm; Chronobiology International - 9(4)ages 314-321 - Informa Healthcare . Whether or not some nocturnal hobby species are adapted for "moonlighting" hasn't hit the literature yet as far as I can tell. It seems that the current night lighting for tanks is much stronger than one would expect in the wild. It was my understanding, anyway, that the night lighting was strictly for the corals of salt water tanks. JSTOR: An Error Occurred Setting Your User Cookie


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## wimvanvelzen (Nov 1, 2008)

Thanks for the links! The points seems to be: how much lux is found at night in the natural habitats of our frogs? And is that amount adequately available in our tanks from say the street lights, lights in the house (e.g. computer leds) etc? And are the blue LEDS giving too much light, or the wrong colour?

With moon light available most nights, total darkness seems not really natural?


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## wimvanvelzen (Nov 1, 2008)

Thanks for the links! 
The point seems to be: how much lux is found at night in the natural habitats of our frogs? And is that amount adequately available in our tanks from say the street lights, lights in the house (e.g. computer leds) etc? 
And are the blue LEDS giving too much light, or the wrong colour?

With moon light available most nights, total darkness seems not really natural?


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## Occidentalis (Jul 11, 2009)

My thoughts would be that under heavy canopy cover, and inside a brom or concealed under a leaf, a dendrobatid would effectively achieve near total darkness. If this is possible in an enclosure with lights directly above, I do not know.

With the blue LED's, it seems as if both is the case. Too much light, at or near the perfect wavelengths for circadian disruption.


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## poimandres (Mar 28, 2009)

Just my $.02...don't know much about circadian rhythms.

I've spent months in the Amazon and it really is remarkable just how little light penetrates the canopy. Unless your on the river, one of the tributaries, or along the banks of a lake or pond, you just don't see the sun or moon. The direct lights that we have in our vivs is magnitudes brighter than what the frogs would be exposed to in their natural habitat. Even at noon when the sun is directly overhead 90% of the forest floor is in darkness (about as bright as what most of us experience an hour or so before sunrise (or after sunset). As for moonlight, on full moon nights there is definitely an indirect and faint ambient glow but I don't think that this is replicable in captivity unless we set up a faint light source outside and far enough away from the viv. It is really faint and just enough to see outlines of trees and objects. Needless to say, in the rainforest at night whether it is a full or new moon, it gets really dark!

As for my own lighting, I run 18/6 prior to introducing frogs in order to induce plant growth and 12/12 once the frogs are introduced.


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## Chris155hp (Mar 17, 2010)

What about red light? is that ok or the least harmful false "moonlight"?


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