By Kiley Haberman (University of Vermont)
Scorpions are among the earliest forms of land animal, and their basic body plan has remained relatively unchanged for hundreds of millions of years. The earliest known fossil scorpions date back 425 to 450 million years, 200 million years before the first dinosaurs roamed the earth. There are more than 1500 scorpion species worldwide, more than 130 occurring in Southern Africa.
Many of the species we have seen are burrowing scorpions with holes that can be deeper than a meter. The deeper they dig their burrow, the cooler and more humid the environment is within that burrow. During winter months, they will close off their burrow by pushing substrate from the inside to block the hole. Two of the scorpion families we have seen more are the Buthidae and Scorpionidae. In the Buthidae family, we have seen scorpions in the Parabuthus genus. Those are ones with large stingers and relatively small pincers. In the Scorpionidae family, we often see scorpions within the Opistophthalmus genus which have a small stinger and large pincers. One way we have learned to tell the level of threat to humans is by the size of the stinger and the pincers. Those with a large stinger and small pincers will carry more dangerous venom, while ones with small stingers and larger pincers are not nearly as dangerous. Both of the Parabuthus and the Opistopthalamus are burrowers.
They are nocturnal creatures and typically solitary. They leave their burrows at night in search of food. Some scorpions go out and forage for their food, while many others are “sit-and-wait” or “ambush” predators. They will wait outside of their burrow or nearby vegetation with their pincers opened until they feel the vibrations of the movement from special hairs on their exoskeleton. Scorpions will eat just about any animal they are capable of overpowering, such as insects, spiders and earthworms. Some larger scorpions will prey upon small vertebrates, small reptiles, mammals and amphibians on occasion.
When using an ultraviolet light, also known as a black light, scorpions can be easily spotted during the night. The UV light reflects off the hyaline layer in the exoskeleton, resulting in an eerie greenish glow. At each campsite, a few students and instructors will go out a few nights around camp looking for scorpions. By simply swaying the light back and forth, the scorpions can be easily spotted. We often find them under twigs, leaves or other vegetation.
While camping in Xai Xai after a long day of work, we decided to go out on a little excursion we like to call ‘scorpin’. We were moving the black light around the ground and saw some commotion around a bright green, glowing scorpion. We moved closer and realized there was an intense battle between a solifugae and a spider. A solifugae is an arachnid also known as the camel spider or sun spider. It is kind of like a mix between a scorpion and spider, but is neither a true scorpion nor a true spider. It is more closely related to scorpions, but does not have a stinger and happens to look more like a spider.
Solifugae
The solifugae was spinning around trying to grasp the tail of the scorpion, as the scorpion attempted to swing his body around the other way and pinch the solifugae. Things were happening so quickly, the solifugae was able to get a good grasp on the scorpion in the middle of its body and started running off with it. All of a sudden, we saw something fall off of the scorpion, a small speck glowing on the ground. Sometimes when a scorpion is being attacked, it will discard the end of their tail in hopes of escape, with a closer look, we found out it was its stinger. A few seconds after stinger fell off, the solifugae dropped him and walked off about a foot away. At this point, neither of them moved. The scorpion curled his legs and pinchers in toward his body, leaving defense mode. The solifugae was resting beneath leaf litter. Minutes went by, they both were motionless. Was the solifugae stung by the scorpion? Did the solifugae deliver a bite so traumatic the scorpion could no longer go on? The detachment of the stinger would not kill the scorpion, but something happened in all of that commotion that caused both arachnids to end their fight, the scorpion not even attempting to move into hiding. We stood there for a while, still no movement. We decided to move on but marked a line in the sand of the area we left them to see if they were still there when we returned the next morning. We went on looking around and didn’t find anything else that night. The next morning around 6 am I went back to check and neither the scorpion nor the solifugae was there. I’ll never know what really happened, but, man, it was a cool thing to watch.