The Arizona bark scorpion, is a small light brown scorpion common to the Sonoran Desert
in southwest United States and northern Mexico. An adult male can reach 8 cm in length, while
a female is slightly smaller, with a maximum length of 7 cm.
Diet The bark scorpion is nocturnal and prefers
to ambush its prey, usually feeding on crickets, roaches, beetles, and other small insects.
Predators Bark scorpions are eaten by a wide variety
of animals such as birds, reptiles, and other invertebrates. Some examples include spiders,
snakes, peccaries, rodents, and other scorpions. Development, pesticides and collecting scorpions
for research or the pet trade also has an impact on the bark scorpion population.
The painful and potentially deadly venom of Bark Scorpions have little effect on grasshopper
mice. Scientists have found the scorpion toxin acts as an analgesic rather than a pain stimulant
in grasshopper mice. Life cycle
Arizona bark scorpions have a gestation period of several months, are born live, and are
gently guided onto their mother's back. The female usually gives birth to anywhere from
25 to 35 young. These remain with their mother until their first molt, which can be up to
3 weeks after birth. Arizona bark scorpions may live up to 6 years.
While nearly all scorpions are solitary, the Arizona bark scorpion is a rare exception:
during winter, packs of 20 to 30 scorpions can congregate.
Bark scorpions, like most other scorpions, are incredibly resilient. Contrary to popular
belief however, freezing scorpions will indeed kill them. They do not thaw and spring back
to life. During US nuclear testing, scorpions, along with cockroaches and lizards, were found
near ground zero with no recorded adverse effects.
Habitat The bark scorpion is particularly well adapted
to the desert: layers of fat on its exoskeleton make it resistant to water loss. Nevertheless,
bark scorpions hide during the heat of the day, typically under rocks, wood piles, or
tree bark. Bark scorpions do not burrow, and are commonly found in homes, requiring only
1/16 of an inch for entry. Arizona bark scorpions prefer riparian areas
with mesquite, cottonwood, and sycamore groves, all of which have sufficient moisture and
humidity to support insects and other prey species. The popularity of irrigated lawns,
and other systems which increase environmental humidity in residential areas, has led to
a massive increase in the number of these animals in some areas.
Centuroides scorpions are unusual in that they are the only genus in the southwest that
can climb walls, trees, and other objects with a sufficiently rough surface. Bark scorpions
practice negative geotaxis, preferring an upside down orientation, which often results
in people being stung due to the scorpion being on the underside of an object.
Venom
The bark scorpion is the most venomous scorpion in North America, and its venom can cause
severe pain in adult humans, typically lasting between 24 to 72 hours. Temporary dysfunction
in the area stung is common; e.g. a hand or possibly arm can be immobilized or experience
convulsions. It also may cause the loss of breath for a short period of time. Due to
the extreme pain induced, many victims describe sensations of electrical jolts after envenomation.
Fatalities from scorpion envenomation in the USA are rare and are limited to small animals,
small children, the elderly, and adults with compromised immune systems. Extreme reaction
to the venom is indicated by numbness, frothing at the mouth, paralysis, and a neuromotor
syndrome that may be confused with a seizure and that may make breathing difficult, particularly
for small children. Two recorded fatalities have occurred in the state of Arizona since
1968; the number of victims stung each year in Arizona is estimated to be in the thousands.
In Mexico, more than 100,000 people are stung annually, and during a peak period in the
1980s, the bark scorpion claimed up to 800 lives there.
Antivenom
An antivenin was developed for this species at Arizona State University, and produced
in quantities sufficient to treat individuals within the state of Arizona. This antivenom
was not FDA approved, but use within the state of Arizona was allowable and very successful
in shortening the duration of symptoms and hospitalization. Production of this antivenin
ceased by 2000 and the product was unavailable by 2004. A Mexican-produced antivenom, Anascorp
[Antivenin Centruroides F(ab′)2, Laboratorios Silanes, Instituto Bioclon SA de CV], received
FDA approval on August 3, 2011 and is now in use.
First aid Basic first aid measures can be used to help
remediate scorpion stings: Clean sting site with soap and water
Apply a cool compress Take acetaminophen or ibuprofen for local
pain and swelling Medical emergencies
Since the amount of venom a scorpion injects varies, Arizona poison control centers suggest
immediate medical attention only in the event of extreme pain or stings involving weaker
individuals. UV lighting
Bark scorpions, like most other scorpions, will glow when exposed to a blacklight. This
is particularly useful in scorpion detection, since bark scorpions are active during the
night, and can be easily spotted using this method. Typical UV LED flashlights are able
to readily detect scorpions at a distance of approximately 6 feet. Newly molted scorpions
will not glow under Ultraviolet light for a few days after molting.
References
External links
Media related to Centruroides sculpturatus at Wikimedia Commons
Further information on the scorpion Holland, Ben. "Scorpion Sweepers".