What makes scorpions glow in ultraviolet light?
March 30, 2020 10:44 AM Subscribe
"Most scorpions glow a blue-green color when illuminated by ultraviolet light or natural moonlight (Kids Discover). Scientists aren't sure how this fluorescence benefits the creatures, but some have speculated (LiveScience) that it acts as a sunscreen, or helps them find mates in the dark. Now, researchers reporting in ACS' Journal of Natural Products (abstract) have identified a new fluorescent compound from scorpion exoskeletons. The team says that the compound could protect these arachnids from parasites." (American Chemical Society) Related: How To Hunt Scorpions At Night With A UV Flashlight (Youtube)
I grew up in southern NM and for a while there was a period when you had to actively shake your shoes and turn them over in case there was a scorpion in them. It was some kind of weird infestation that didn't last forever. But it was a real possibility to find a scorpion in your shoes for a while in my neighborhood when I was maybe 11 or 12.
Scorpions are horrifying/fascinating creatures. Their glowy nature is fascinating.
posted by hippybear at 11:00 AM on March 30, 2020 [1 favorite]
Scorpions are horrifying/fascinating creatures. Their glowy nature is fascinating.
posted by hippybear at 11:00 AM on March 30, 2020 [1 favorite]
Proteins are the most amazing things ever come up with by nature.
posted by Your Childhood Pet Rock at 11:05 AM on March 30, 2020
posted by Your Childhood Pet Rock at 11:05 AM on March 30, 2020
It's so they look cool at scorpion raves. Duh.
posted by escape from the potato planet at 11:24 AM on March 30, 2020 [7 favorites]
posted by escape from the potato planet at 11:24 AM on March 30, 2020 [7 favorites]
Some owls have feathers that fluoresce under UV light, and it can be used to age them.
posted by mollweide at 12:28 PM on March 30, 2020 [4 favorites]
posted by mollweide at 12:28 PM on March 30, 2020 [4 favorites]
Proteins are the most amazing things ever come up with by nature.
So, the fluorescent compound in question isn't a protein. It's a macrocycle that looks similar to a crown ether.
Interestingly, if you were looking at the image above like a sophomore organic chemistry student, you would not expect each of the individual aromatic (benzene) rings in the structure to be fluorescent by themselves.....and by themselves they are not fluorescent!
If you showed the above cartoon to a first year grad student, they would likely predict that the floppy chains between the aromatic rings would fold up to allow the rings stack on top of each other because of of π-stacking (and in water, hydrophobic) forces.
Further, if asked "do you think this molecule would fluoresce" these grad students would predict that these stacked rings form an intramolecular excimer, and yes, the molecule would fluoresce! This is probably the mechanism of fluorescence in this scorpion.
This is another great example of the explanatory and predictive power of simple molecular line-bond drawings: being able to predict, by examination, simple conformational (shape) properties of molecules leading directly to their bulk, physical, real world behavior.
posted by lalochezia at 1:03 PM on March 30, 2020 [11 favorites]
So, the fluorescent compound in question isn't a protein. It's a macrocycle that looks similar to a crown ether.
Interestingly, if you were looking at the image above like a sophomore organic chemistry student, you would not expect each of the individual aromatic (benzene) rings in the structure to be fluorescent by themselves.....and by themselves they are not fluorescent!
If you showed the above cartoon to a first year grad student, they would likely predict that the floppy chains between the aromatic rings would fold up to allow the rings stack on top of each other because of of π-stacking (and in water, hydrophobic) forces.
Further, if asked "do you think this molecule would fluoresce" these grad students would predict that these stacked rings form an intramolecular excimer, and yes, the molecule would fluoresce! This is probably the mechanism of fluorescence in this scorpion.
This is another great example of the explanatory and predictive power of simple molecular line-bond drawings: being able to predict, by examination, simple conformational (shape) properties of molecules leading directly to their bulk, physical, real world behavior.
posted by lalochezia at 1:03 PM on March 30, 2020 [11 favorites]
I'm wondering whether this fluorescence could be part of a fluorescent cooling cycle.
Something like, the compound absorbs an ultraviolet photon, some of which is converted to a metastable excited state, and some of which is converted to heat; the heat is reradiated as much as possible, and the excited molecule then has inelastic collisions with its environment which raise its energy level to the point it can emit a photon of fluorescent light which carries away the energy of the original metastable state as well as energy transferred in the inelastic collisions, resulting in a net cooling effect.
I can't help thinking that the molecule in lalochezia's first link looks as if it would vibrate like a tuning fork.
posted by jamjam at 1:37 PM on March 30, 2020 [1 favorite]
Something like, the compound absorbs an ultraviolet photon, some of which is converted to a metastable excited state, and some of which is converted to heat; the heat is reradiated as much as possible, and the excited molecule then has inelastic collisions with its environment which raise its energy level to the point it can emit a photon of fluorescent light which carries away the energy of the original metastable state as well as energy transferred in the inelastic collisions, resulting in a net cooling effect.
I can't help thinking that the molecule in lalochezia's first link looks as if it would vibrate like a tuning fork.
posted by jamjam at 1:37 PM on March 30, 2020 [1 favorite]
scorpion going into tiny hole-in-the-ground home
posted by amtho at 1:44 PM on March 30, 2020 [2 favorites]
posted by amtho at 1:44 PM on March 30, 2020 [2 favorites]
But what would be really wonderful (keeping in mind Phillip Morrison's dictum "nothing is too wonderful to be true!") is if the molecule absorbed a single UV photon, then absorbed additional energy from its environment via inelastic collisions, and then emitted two photons of blue light, the energy of which added up to more than the energy of the original UV photon.
That would be some sophisticated cooling!
It would be essentially a time-reversed version of second harmonic generation with a little extra added energy from inelastic collisions.
posted by jamjam at 2:12 PM on March 30, 2020
That would be some sophisticated cooling!
It would be essentially a time-reversed version of second harmonic generation with a little extra added energy from inelastic collisions.
posted by jamjam at 2:12 PM on March 30, 2020
Related: The Amazon reviews of Ultraviolet Flashlights are pretty entertaining.
posted by Liquidwolf at 2:27 PM on March 30, 2020 [1 favorite]
posted by Liquidwolf at 2:27 PM on March 30, 2020 [1 favorite]
Fascinating. A question. The post says "Most scorpions glow a blue-green color when illuminated by ultraviolet light or natural moonlight". I was told in the past that it was all scorpions, and FWIW, the first link says "all scorpions". Is there some kind of unusual scorpion that DOESN'T fluoresce under UV light? If so, it seems like comparing it to other species would illuminate (pun intended) this phenomenon.
I guess what I'm saying is, "Help! Is there an arachnologist in the house?"
posted by tom_r at 2:50 PM on March 30, 2020
I guess what I'm saying is, "Help! Is there an arachnologist in the house?"
posted by tom_r at 2:50 PM on March 30, 2020
I've seen them perform live and I can say with confidence that The Scorpions don't glow under ultraviolet light.
posted by hippybear at 2:55 PM on March 30, 2020 [5 favorites]
posted by hippybear at 2:55 PM on March 30, 2020 [5 favorites]
I have used my UV flashlight to hunt down two brilliantly fluorescent scorpions in or near my closet in the past year. Only one of which stung me before I turned the light on it.
Bark scorpion stings hurt. Like, extra strength Tylenol, a bunch of weed and Netflix for the day kind of hurt.
I now have a designated scorpion-killing hammer, though. So that's nice.
If there's a new breed of scorpion around that doesn't fluoresce under ultraviolet light, I'm just done. That's like scorpion ninjas. Screw that, I'm moving to Milwaukee.
posted by MrVisible at 11:19 PM on March 30, 2020 [2 favorites]
Bark scorpion stings hurt. Like, extra strength Tylenol, a bunch of weed and Netflix for the day kind of hurt.
I now have a designated scorpion-killing hammer, though. So that's nice.
If there's a new breed of scorpion around that doesn't fluoresce under ultraviolet light, I'm just done. That's like scorpion ninjas. Screw that, I'm moving to Milwaukee.
posted by MrVisible at 11:19 PM on March 30, 2020 [2 favorites]
Not only scorpions, there's a huge number of spiders that flouresce as well. In my opinion, any explanation for the florescence in scorpions must deal with these related taxa.
posted by dhruva at 10:22 AM on March 31, 2020
posted by dhruva at 10:22 AM on March 31, 2020
The problem with the UV florescence for communication hypothesis is that these UV signals are only seen when UV light is shone on the animals. In daylight this signal is completely swamped by sunlight and at night, there is no UV source to trigger these signals. The parasitism avoidance hypothesis is interesting, but will have to be tested, somehow.
posted by dhruva at 10:27 AM on March 31, 2020
posted by dhruva at 10:27 AM on March 31, 2020
MrVisible: Las Cruces is so much the Tucson of New Mexico it's not even funny. No wonder you're finding scorpions in your house. I hope the plague passes soon.
I hope all the plagues pass soon.
posted by hippybear at 9:30 PM on March 31, 2020 [1 favorite]
I hope all the plagues pass soon.
posted by hippybear at 9:30 PM on March 31, 2020 [1 favorite]
« Older Fighting Covid-19 Misinformation | Need a little break? Newer »
This thread has been archived and is closed to new comments
posted by not_the_water at 10:45 AM on March 30, 2020 [4 favorites]