For today’s post I am presenting a few photos taken of a very common arachnid found in glades and drier forests of southern Missouri – the Striped Bark Scorpion. No, there is no reason to fear these secretive scorpions; they are only dangerous if you happen to be an arthropod smaller than they are. They are, however, much more common than I ever would have expected. Steve and I had much success finding them in the glades of Hughes Mountain Natural Area this past summer. Wait until the sun has well set, turn on your blacklight and walk around for a while. We were finding them easily every few steps.
The photo above shows what they look like to the naked eye (illuminated by flash). These guys are extremely fast as well as stealthy. The use of blacklight is almost mandatory to efficiently find them. These lights as well as a typical flashlight/torch brings all sorts of other arthropod visitors to the glade top as well.
So, why do they glow under ultraviolet light? This is an interesting question that has not yet been satisfactory answered by those who study these creatures. Hypothesis range from helping to attract prey, to aiding in their ability to see and sense light. I took the photo above soon after we watched this guy sprint approximately a meter towards us in the blink of an eye. At the time, Steve and I assumed it was a defensive run (or lunge) in reaction to us being near it. It was not until days later that I discovered what the real purpose of that dash had been…
Can you see what that reason was? Here’s a closer look…
Yes, I believe its dash was in capturing a prey – this small wolf spider – probably the only other predator that might be as common or more common than the scorpions themselves in this nocturnal food web.
Thanks for visiting…
OZB
A Thousand Acres of Silphiums 
So many questions about this black light fluorescence. I’m sure you gathered at least as much info as contained in this excerpt from Wiki: “Scorpions are also known to glow a vibrant blue-green when exposed to certain wavelengths of ultraviolet light such as that produced by a black light, due to the presence of fluorescent chemicals in the cuticle. One fluorescent component is now known to be beta-carboline. A hand-held UV lamp has long been a standard tool for nocturnal field surveys of these animals. Fluorescence occurs as a result of sclerotisation and increases in intensity with each successive instar. This fluorescence may have an active role in scorpion light detection.”
Truly fascinating. Would love to know if/how this capacity benefits them.
Never experienced pathos for a wolf spider until now!
Thanks for such great work, as always, my friend.