Arizona bark scorpion

Arizona bark scorpion
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Order:	Scorpiones
Family:	Buthidae
Genus:	Centruroides
Species:	C. sculpturatus
Binomial name
Centruroides sculpturatus (Wood, 1863)

The Arizona bark scorpion (Centruroides sculpturatus, included in Centruroides exilicauda), is a small light brown scorpion common to the southwest United States. The range of the scorpion is the Sonoran Desert. An adult male can reach 8 cm in length (3.14 inches), while a female is slightly smaller, with a maximum length of 7 cm (2.75 inches). ^[1]

Diet

The bark scorpion is nocturnal, prefers to ambush its prey, and usually feeds on crickets or roaches.

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.

Life cycle

Three adult and four juvenile Arizona bark scorpions

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 between 25–35 young, and the young will remain with their mother until their first molt, 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.^[2]

Bark scorpions, like most other scorpions, are incredibly resilient. During US nuclear testing, scorpions, along with cockroaches and lizards, were found near ground zero with no recorded adverse effects.^[3]

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.^[4]

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. They seem to be unable to scale smooth surfaces. These being, but not limited to glass, smooth metal, and smooth plastic. 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.^[5]

Venom

Frontal view of a bark scorpion in a defensive posture

The bark scorpion is the most venomous scorpion in North America, and its venom can cause severe pain (coupled with numbness and tingling) 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 (including small pets), small children, 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.^[2]

Antivenom

An antivenom was developed for this species at Arizona State University^[6] and produced in quantities sufficient to treat individuals within the state of Arizona up until 1999.^[7] FDA approval was not required as it was provided at no charge, and use was restricted to within the state of Arizona; it was very successful in shortening the duration of symptoms and hospitalization. Production of this antivenom ceased by 2000 and the product was unavailable by 2004. A Mexican-produced antivenom, Anascorp [Antivenin Centruroides (scorpion) F(ab′)_², Laboratorios Silanes, Instituto Bioclon SA de CV], is being tested and used in its place.^[8] On August 3, 2011, the FDA approved Anascorp for use in the United States.^[9]

First aid

Basic first aid measures can be used to help remediate scorpion stings:^[8]

• Clean sting site with soap and water
• Apply a cool compress (cool cloth, no ice)
• Take acetaminophen (paracetamol) or ibuprofen for local pain and swelling

Natural remedies include using the pulp from the prickly pear cactus on the sting site.

Medical emergencies

AZ bark scorpion glowing under ultraviolet light

Since the amount of venom the scorpion injects on a sting varies, Arizona poison control centers suggest immediate medical attention only in the event of extreme pain or stings involving children.^[3]

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

1. ^ "Species Centruroides sculpturatus - Arizona bark scorpion". http://bugguide.net/node/view/45899. Retrieved June 18, 2008. 
2. ^ ^{a b} "Scorpions". Cooperative Extension, College of Agriculture & Life Sciences. University of Arizona. Archived from the original on July 21, 2010. http://web.archive.org/web/20100721230743/http://ag.arizona.edu/pubs/insects/az1223/. Retrieved June 20, 2008. 
3. ^ ^{a b} "Poison and Drug Information Center". University of Arizona. 2008. Archived from the original on August 20, 2010. http://web.archive.org/web/20100820192450/http://www.pharmacy.arizona.edu/outreach/poison/scorpions.php. Retrieved June 20, 2008. 
4. ^ "Scorpion Management Guidelines". 2008. http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74110.html. Retrieved June 18, 2008. 
5. ^ Phillips S.; Comus P. (2000). A Natural History of the Sonoran Desert. Arizona Sonora Desert Museum. p. 292. ISBN 0-520-2190-5. 
6. ^ Glenn Derene (May 10, 2010). "Why snakebites are about to get a lot more deadly". Popular Mechanics. http://www.popularmechanics.com/science/health/snakebites-about-to-get-more-deadly. Retrieved September 23, 2011. 
7. ^ Ken Alltucker (August 4, 2011). "Scorpion antivenin gets FDA's OK". The Arizona Republic. http://www.azcentral.com/business/articles/2011/08/04/20110804scorpion-antivenin-gets-fda-ok.html. Retrieved September 23, 2011. 
8. ^ ^{a b} David Von Behren, MPH (2000). "Soothing the Scorpion's Sting". University of Arizona. Archived from the original on June 3, 2009. http://web.archive.org/web/20090603092350/http://www.opa.medicine.arizona.edu/horizons/2000/fall/pg21.htm. Retrieved June 20, 2008. 
9. ^ "FDA approves the first specific treatment for scorpion stings". FDA. August 3, 2011. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm266611.htm. 

External links

Arthropods portal

• Further information on the scorpion
• Holland, Ben (2008). "Scorpion Sweepers". http://www.scorpsweep.com/facts.html.