Fluorescent Scorpions

I'm not an expert in the field of arachnology. On the contrary, I'm slightly arachnophobic and prefer to stay away from arachnids altogether. But when I was looking for scientific articles that sounded (for lack of a better term) 'exciting', an article on scorpions caught my attention. I had no idea that when you shove scorpions under UV light, they look like this:

The first thought that occurred to me when I saw this? "Ooooh! Pretty!" And that's one of the reasons I decided this topic was worth investigating.

So, scorpions fluoresce under UV light, and for the longest time it was believed that this phenomenon occurs for no apparent reason. But if I've learned anything over the past year and a half at RIT, it is that in nature, very rarely do things happen for no apparent reason. Kloock et al seem to agree with me. Which could very well be why they decided to try and find out if scorpion fluorescence is a tool that helps these animals detect UV light.

What the authors did was conduct a simple two choice experiment. They used two groups of scorpions: one group was kept under UV light till their fluorescence disappeared, and the other was not. Individuals from both groups were kept in Petri dishes that were divided into two hemispheres: one hemisphere was painted black in order to prevent light from entering it, and the other was not. Their movement was recorded with the help of video cameras, and their behavior was tested under three conditions:

• Infrared light only
• Infrared and Ultraviolet light
• Infrared and white light

The results, in a way, supported the hypothesis that fluorescence helps scorpions detect UV light at low levels, but there were remarkable differences in the activity levels of the two groups. However, it wasn't the results that concerned me. The methods were what I focused on while reading the paper.

So here are my final thoughts on the paper:

• Not all of the substances that cause the fluorescence have been identified and isolated. 
• How does frying scorpions under UV light affect them (other than the obvious reduction in fluorescence)? Perhaps there's something else about the scorpions that helps them detect UV light, which got destroyed under the influence of UV light?
• Would male scorpions behave any differently?

While Kloock's experiments give us a few interesting results, it doesn't help prove much. We're probably one step closer to figuring out the mystery behind fluorescence in scorpions, but arachnologists still have a long way to go.


Link to paper: Ultraviolet light detection: a function of scorpion fluorescence