Scorpions glow in the dark to detect moonlight...???

Galapoheros

ArachnoGod
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Thanks, that's interesting, makes a person think about it more. It can bother me sometimes to see things float around like this posed as a fact though, hasn't happened with this article but I won't be surprised to see the theory stated as fact at some point, that happens often. Other things could have happened to the scorpions exposed to more UV. Could they have had sight damage or could enough exposure to the UV have caused some damage another way that made them randomly walk, maybe even being in a little pain, invert confusion lol?
 

JesseD

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Damage by the UV is what I think too. The guy's theory is interesting; however I don't think this is the way to prove it. You go shine black light on your eyes for an extended period of time and keep them open too!
 

skinheaddave

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Kloock has put out a few interesting papers over the last few years on fluorecence-related matters. Can't wait to read the paper on this one.

Cheer,
Dave
 

ScorpDude

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A very interesting paper, I was however under the impression could not see both the UV light or the emission wagelengths. Supposing they can, would it not make more sense for there to be concentrated areas of the pigmentation in areas readily visable by the scorpions, ie the insides of the chelicerae and to an extent the prosoma? This is in contrast to the matte uniform fluorescence witnessed.
 

VickyChaiTea

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HEY! I used to live in Bakersfield! NEAT!

Though I thought they only glowed under blakclights, and not natural moonlight?
 

skinheaddave

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I was however under the impression could not see both the UV light or the emission wagelengths.
The Zwicky papers on spectral sensitivity suggest that they can see the emmited light. I forget what it had to say about the UV but I believe that the peak wavelength that causes fluorescense is beyond their sensitivity.

Supposing they can, would it not make more sense for there to be concentrated areas of the pigmentation in areas readily visable by the scorpions,
Well we know that the compounds that actually fluroesce are related to cuticle hardening .. so there may be some restrictions to eliminating it. You have to remember that the mechanisms of evolution are not those used by an engineer. It would make a lot more sense for humans to have bulked up knees ... but we don't. The classic text "The Spandrels of San Marco" is a good one to read if you haven't.

Cheers,
Dave
 

ScorpDude

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Well we know that the compounds that actually fluroesce are related to cuticle hardening .. so there may be some restrictions to eliminating it. You have to remember that the mechanisms of evolution are not those used by an engineer. It would make a lot more sense for humans to have bulked up knees ... but we don't. The classic text "The Spandrels of San Marco" is a good one to read if you haven't.

Cheers,
Dave
True true, and I certainly favour the sclerotization hypotheses put forward that you mentioned. I suppose the key difference between the human knee example you mentioned and the scorpion pigmentation is the evolutionary time scales we're talking about. Of course it could be that overall pigmentation simply isn't maladaptive enough to cause its removal so to speak, even over the extensive evolutionary time period. I guess my point is that if its for signalling to the scorpion, one would assume the scorpion would want to signal just for its own devices, not light up its whole body. But then of course we come back to the primary function of sclerotization.

That said, I confess not to knowing the subject as well as you or the author, but its always fun to shoot hoops with people wiser than myself.
 

DrAce

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That strikes me as a neat experiment, with what I can think of as a really neat set of controls.

Another option would be to do the exact same thing, but creating a 'knockout' scorpion... where one of the genes responsible for creating the fluorescent pigment is gone (are there scorpions which naturally lack this pigment fluorescence? Those would be an analagous group).

Then repeat the whole experiment again. My guess, if he's right, is that they will not change behaviour from the UV exposure.
 

Michiel

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That strikes me as a neat experiment, with what I can think of as a really neat set of controls.

Another option would be to do the exact same thing, but creating a 'knockout' scorpion... where one of the genes responsible for creating the fluorescent pigment is gone (are there scorpions which naturally lack this pigment fluorescence? Those would be an analagous group).

Then repeat the whole experiment again. My guess, if he's right, is that they will not change behaviour from the UV exposure.

Nope, all scorpions fluoresce under 395 Nm UV light. Some brighter than others, but they all do..........There is a story going around that members of the genus Chaerilus would not fluoresce, and I used to believe this too, untill I received some species of this genus.
I feel I don't have a helicopterview and have read several theories.......It could be pure coincidence and without a function....Remember scorpions remain over 90% (or more) of their time in burrows or other hides.......so, they want a little disco light in their burrows????? (so why would evolution develope/ provide something for this organism that has no use 90% of it's life??????) Evolution is not always a strict lineair process, it can also be a series of coincidences that lead to adaptation..........
 

skinheaddave

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Another option would be to do the exact same thing, but creating a 'knockout' scorpion... where one of the genes responsible for creating the fluorescent pigment is gone
The problem with this is that the compounds ARE involved in the hardening of the exoskeleton. Modifying the mechanism by which those chemicals are formed may have severe implications on the survival of that specimen.

Cheers,
Dave
 

DrAce

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The problem with this is that the compounds ARE involved in the hardening of the exoskeleton. Modifying the mechanism by which those chemicals are formed may have severe implications on the survival of that specimen.

Cheers,
Dave
Oh, they are? See - I've never looked into scorpion exoskeletal structure.

Do you happen to have a PDF of something discussing this, for the lazy bugger who could probably google it? What is the chemical responsible, do you have that off hand? I'm curious now.
 

Travis K

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Maybe the over exposed UV scorps were 'blinded' from the UV light or at least had depleted visual ability and thus were not able to tell if the night sky was bright with moon and stars or pitch black?

I think they would be able to detect 'normal' wave lengths better than the there own natural glow. To me they look as dark as every thing else on full moon nights with out the aid of a UV flash light.
 

esotericman

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The published sensitivity spectra seem to have a minor peaks in the 490-520 range, but are very weak compared to the UV sensitive receptors. Quite a bit of literature also shows differential sensitivity between the eye based on location on the body and if they're "dark adapted" or not.

I really wish people would check the literature BEFORE publishing, even with google scholar you can get pretty far down the road without access to huge university libraries and systems.
 

DrAce

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Maybe the over exposed UV scorps were 'blinded' from the UV light or at least had depleted visual ability and thus were not able to tell if the night sky was bright with moon and stars or pitch black?

I think they would be able to detect 'normal' wave lengths better than the there own natural glow. To me they look as dark as every thing else on full moon nights with out the aid of a UV flash light.
It's definitely a possibility, but I don't buy it.

Incidentally, the guy actually exposed his scorpions to less UV than previous experiments. It's a POSSIBILITY, yes. Which would be obviated in my experiment above (which, apparently, won't work).

Another option would be the same experiment, with some sort of shielding applied to their eyes.
 
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