Fluorescence in Scorpions
- Yes, all scorpions fluoresce under UV light (also known as "blacklight").
- Longwave ultraviolet light is reflected as visible light in the green
range. In darkness, the scorpions appear to glow. Under direct sunlight,
the fluorescence may impart a greenish tint to the scorpion's color.
The fluorescence is caused by an unidentified substance in a very
thin layer in the cuticle of the scorpion called the hyaline layer. Newly
molted scorpions do not fluoresce. As the new cuticle hardens, the fluorescent
quality increases. This indicates that the fluorescent factor is either
secreted by the scorpion shortly after molting or that the fluorescence
is a by-product of the tanning process. Alcohol in which scorpions have
been preserved may also fluoresce. The hyaline layer of the cuticle is
very tough stuff. It is often found in scorpion fossils. Even after hundreds
of millions of years, while all the other layers of the cuticle have been
lost, this hyaline layer remains embedded in fossil rocks. And yes, it
still fluoresces. Nobody knows the function of the hyaline cuticle or its
strange fluorescence. Some have suggested that it serves as UV sensor (all
scorpions are basically nocturnal and shun the light). This unusual feature
can make scorpions easier to collect and observe. When darkness falls,
portable UV lights can be carried into the field where scorpions live.
Scorpions caught in the nearly invisible UV light glow an eerie greenish
color, making them easy to spot in the darkness.
In the 1980s we used a neat battery powered lantern called a "Safari
Lite." They were fluorescent lamps powered by two 69 volt batteries. We
replaced the ordinary fluorescent tube with a UV tube and we were in business.
The Safari Lite put out some strong light. You could see scorps, even small
ones, at 15-20 meters if it was really dark out. To the best of my knowledge,
they stopped making the batteries (which were quite expensive and not rechargeable).
- Most recently, I have used a rig designed for inspecting leaks using
fluorescent indicators. I purchased my "Watertight UV Lamp" system (L-00295-00)
from Cole-Parmer
Instrument Company. The system runs off of two 6-volt lantern batteries
and has a watertight fluorescent UV wand. The wand is completely sealed
so the UV tube cannot be replaced (bummer). I had to fashion a sheet metal
reflector to keep the light from shining on me (the wand provides 360 degree
illumination), but other than that it worked fine. When I bought it it
was US$45.00, but check with them for availablilty and pricing. I also
found that my older rigged-up UV wand from BioQuip could run off of the
same power supply. Bioquip (BioQuip Products, 2321 Gladwick Street, Rancho
Dominguez, CA 90220, USA; Phone: (310) 667-8800 Fax: (310) 667-8808; email: BioQuip)
also sells a UV light wand and rechargeable battery packs (Catalog Number
2813B and 2813C for the light wands; 2860 and 2861 for the rechargeable
battery packs). These are a little more expensive than the Cole-Parmer
rig, but are of similar design.
- I have also used a couple of other camping lanterns. They have the same
design as the old safari light, but run off of two 6-volt lantern batteries
or rechargeable batteries. The 12-volt system worked well, but the rechargeable
system was a little under-powered. Cole-Parmer
Instrument Company used to sell a rechargeable lantern. You should
check with them for availability and pricing. You generally have to find
a really good camping or army surplus store to pick up one of the six volt
models. Just remember that the UV tube has to be of the "blacklight" (long-wave)
variety, not of the germicidal variety used in a lot of scientific applications.
-
- Disclaimer: The views expressed here are mine alone
and do not represent the views of the Department of the Army or the Smithsonian
Institution... or anybody else for that matter. - Dr. Scott A. Stockwell
