Techniques

The discovery that scorpions fluoresce under ultraviolet light totally revolutionized the study of scorpions. A compound in the exoskeleton, called a coumarin, refracts ultra-violet light in the visible spectrum, usually green, and causes them to glow. Under ultra-violet light they become creeping green beacons, almost shouting, "here I am!" in the night. With the aid of portable blacklights, it is now much easier for scientists to watch these animals in the field and collect them for research in a lab.

While blacklighting, it is not unusual to find yourself literally surrounded by brilliant green arachnids. Its fun to watch them hunt, burrow, mate and go about their amazing little lives. This is especially true with Smeringurus mesaensis in southern California and Arizona, where they are often so abundant that I have even seen them eating each other!

The only shortcoming with blacklights is that portable systems are hard to find and the better lights are usually built at home. So far, I have found three options for those who wish to collect scorpions using blacklights, which I strongly suggest. There is nothing better than a warm desert night collecting scorpions under the hazy purple glow of a blacklight.

OPTION 1: Fluorescent UV tubes
A blacklight gas tube system can be constructed by anyone with a few common tools, and the materials can easily be purchased in most hardware stores. The fluorescent UV tubes usually come in several sizes and housings can be bought to hold one or several tubes at a time. A little electrical work is required but employees at such stores should be able to help you with any technical questions. Below is a diagram of a typical two tube system used by Dr. Victor Fet while collecting exotic specimens like Pseudochactus in the Middle East.

Visit Dr. Fet's webpage for a picture of this blacklight in action.  http://www.science.marshall.edu/fet/euscorpius/Fet.htm
 

OPTION 2: UV LED's

Recently a paper has been published in Euscorpius, a peer-reviewed online publication, on the construction of a blacklight using lots of UV light emitting diodes (LED's) in a series. To me, this looks like the brightest, most light weight, and overall best option all around. The only problem is that the materials are a little more difficult to acquire and even more tricky to assemble. But still, with the right tools, almost anyone could make one. I plan to build one myself in the near future.

Here is the link to the manuscript from the Euscorpius website. Its a great paper and includes pictures, materials needed, where to get them, and cost.

OPTION 3: Purchasing Premade Portable Blacklights

http://www.blacklite.com/Products/Portable.htm

http://www.micronuv.com/

http://www.tedndt.com/cat/catalog.php?TED=56

There are lots more...

Systematically looking for and flipping over rocks and logs can be another fun and somewhat effective way to look for scorpions. The benefits of this strategy are that it can be used during the day and requires little or no tools.

During the day, scorpions hide either in burrows or under rocks, logs and debris. Rock flipping consists of flipping over rocks and examining the underside and the substrate underneath for scorpions. It sounds easy but can also be very frustrating and often you can spend a whole day flipping rocks and getting nothing but sore and bloody fingers. To make rock flipping a little more effective I have found several tricks and techniques.

Etiquette: Always place rocks and logs back exactly how you found them while careful not to crush any other wildlife underneath.

A. Think like a scorpion.
Where would you hide if you were a scorpion in this specific habitat? What could you fit under that would still protect you from predators and the elements? Is there an opening big enough so that you could notice an insect or prey item go by? An even better way to start would be to ask yourself if a scorpion would even be in this habitat at all!

B. Look for rocks that are flat or have squared off edges.
In my experience, I can not remember ever finding a scorpion under a round rock. First off, round rocks usually lay in the ground and not on top, leaving little or no room for a scorpion to even get underneath. Second, flat rocks usually sit on the surface of a substrate and are not as thick, meaning that warmth from the sun will more easily penetrate the rock and thus warm the scorpion hiding underneath. Remember that scorpions are ectotherms, meaning that their body temperature fluctuates with that of the surroundings, so they really like places that are warm.

C. Make sure there aren't too many rocks.
The problem with too many rocks isn't that scorpions aren't there, its just that there are many more places for them to hide. It won't be worth your time to start flipping every stone in a huge rock pile so look for rocks that are in small groups, scattered, or even all alone. A rock with no other rocks around it becomes the only hiding spot for scorpions so your chances of finding one are greatly increased.

D. Don't pick rocks that are too big or too small.
A rock is usually too small if it can be easily picked up with one hand or is less than 6 inches at it longest point. I've flipped lots of these and almost never find any scorpions, with only one exception (Serradigitus), which are found more abundant under bigger rocks anyway.
A rock is generally too big if you can not lift it on your own. Rocks this heavy usually sink pretty well into the ground and squeeze shut any openings that a scorpion would be able to crawl into. Furthermore, you don't want to waste all your energy that could be used for lifting smaller more appropriate rocks.