Out of the seventy or so species of scorpions that live in North America, the state of Illinois only has a single scorpion species. That is the Striped Bark Scorpion.
Unlike their cousins, the Arizona Bark Scorpions, Striped Bark Scorpions have stings that are no more medically significant than wasp stings. However, all scorpion stings have the potential to cause severe allergic reactions such as anaphylactic shock. If you have blurred vision, muscle spasms, or difficulty breathing after experiencing a scorpion sting, seek immediate medical attention.
Common Striped Bark Scorpion (Centruroides vittatus)
Striped Bark Scorpions, which also go by the common names Plains Scorpion, Wood Scorpion, or Stripe Backed Scorpion, are Buthid Scorpions, just like the Arizona Bark Scorpion. However, their sting is not nearly as dangerous as that of the Arizona Bark scorpion. Common Striped Bark Scorpions are the most common scorpions in the United States. Thousands of people are stung by them each year when they step on them with bare feet or come into accidental contact with them in some other manner.
Unlike Northern Scorpions and Northern Black Hairy Scorpions, which never venture far from their burrows, Striped Bark Scorpions are wandering hunters. Like all bark scorpions, they are natural climbers. Besides living under rocks, they climb trees and fence posts and have no problem climbing the walls of your home. They actually have a negative geotaxis, or in other words, they prefer an upside-down orientation. See
Striped Bark Scorpions live in a variety of environments, such as woodland, grassland, and desert. During the day, they will take shelter under rocks, beneath loose bark, or in wood piles, etcetera.
Like all scorpions, they are nocturnal hunters and will be under shelter until after sundown. What’s more, as all scorpions do, they have fluorescent compounds in their exoskeletons that make them glow under black light. If you are camping in an area where striped bark scorpions are active, it’s a good idea to go armed with an ultraviolet flashlight. Use the ultraviolet light to scan your campsite after dark.
The range of the striped back scorpion begins in the northern Mexico states of Chihuahua, Coahuila, Nuevo Leon, and Tamaulipas. It then extends northward up to the southern counties of Nebraska. Their range also extends longitudinally from the Sangre de Cristo mountains and Rio Grande of New Mexico in the west and the Missouri River and the Mississippi River in the east. The following U.S. states have populations of striped bark scorpions: Arkansas, Colorado, Kansas, Illinois, Louisiana, Mississippi, Missouri, Nebraska, New Mexico, Oklahoma, Florida, Georgia, and Texas.
In areas with colder wintertime temperatures, striped bark scorpions by tolerating limited freezing of their body tissue. These scorpions then hibernate through the winter months.
Where do striped bark scorpions live in Illinois?
Researchers working for the Illinois Department of Natural Resources have collected the most numerous striped bark scorpion specimens on the east bank of the Mississippi River, in close proximity to the town of Fults, which is in Monroe County. Striped bark scorpion specimens have also been collected around Prairie du Rocher in Randolph County.
The IDNR scientists theorize that the striped bark scorpion populations in these two Illinois counties are natural eastward radiations from Missouri. Furthermore, they theorize that their founders crossed the Mississippi River via rafting on flood debris. See However, no one can be completely sure that this is the case.
To prove or disprove this theory, scientists with the Illinois natural history survey have gathered striped back scorpion specimens from the Illinois and Missouri sides of the Mississippi River to genetically compare them. See
What do striped bark scorpions look like?
All scorpions look a little bit like tiny land-dwelling lobsters with some distinctions. Lobsters have 10 legs, while scorpions have 8, and of course, lobsters don’t have a bulbous venom-filled stinger on the end of their tail, while scorpions do.
Adult striped bark scorpions are up to 2 3/4″ long. An adult of this species is uniformly pale yellow in color, with the exception of two longitudinal dark brown stripes that run the length of its back and a dark triangle at the top of their heads.
Striped Bark Scorpion Behavior
Striped Bark Scorpions mate in the fall and also occasionally in spring or early summer. The mating process begins with the male engaging the female scorpion in an elaborate mating dance called the promenade a deux. At this time, the male maneuvers the female to a spot where he can deposit a sperm packet called a spermatophore for her reception.
The male must hold the female over the spermatophore long enough for her to receive it. Therefore, larger males successfully mate a larger percentage of the time. If the female accepts the male’s spermatophore, the pair join together and rub chelicera in the “kiss” stage. At this point, the female takes up the spermatophore. What follows is about an 8-month gestation, after which their offspring are born alive.
After the newborn northern scorpions free themselves from the birth membrane, they will climb up their mother’s walking legs and onto her back. The young scorpions ride there on their mother’s back in a grouped formation, only climbing down to feed on pellets that the female scorpions create for them when she feeds until they are sufficiently old to strike out on their own. This is generally after their first molt. See
Pseudoscorpions in Illinois
Pseudoscorpions, also sometimes called book scorpions or false scorpions, are tiny arachnids that look a lot like a tiny scorpion minus the stinger. They have a flat, pear-shaped body, eight legs, and two long pedipalps with pinchers on the ends, just like scorpions.
People also sometimes mistake these tiny little creatures for ticks. There are over 3,300 pseudoscorpion species worldwide, and their average body length is just 3 millimeters.
Book scorpions don’t have a stinger on their tail. However, they do have a stinger in each pincher. They inject their prey with venom to immobilize it. After which, they secrete a fluid over it to dissolve it so that they can ingest the liquified remains.
Book scorpions are generally beneficial to humans since they prey on pests such as clothes moth larvae, carpet beetle larvae, booklice, ants, mites, and small flies. See
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