Scorpions

Order:  Scorponida
Family: Arachnida
Species: Centruroides vittatus

The notorious scorpion has been around for over 450 million years.  It is depicted as a menacing creature capable of a deadly sting, even though only one of its 75 species possesses this characteristic.

Description

Scorpions are members of the order Scorponida and are in the same class as spiders, ticks and mites.  They are easily recognized by their lobster-like appearance, and by their fleshy tail-like post-abdomen, which ends in a bulbous sac and prominent sting.  Like others in this group, they have four pairs of legs and a combined head and thorax called the cephalothorax.  Scorpions possess large pincers or chelae which they use to capture and hold their victims while feeding.  U.S. scorpions vary in color from black, gray, brown to yellow and are from 1.2 cm to 18.5 cm (1/2 inch to 7 ¼ inch) long.

Life Cycle

Scorpions have a life cycle of two to five years.  They mate in the fall or early spring after a long elaborate courtship dance.  The female bears young seven to twelve months after mating and may produce from 14 to over 100 young in one litter.  The young are carried on the mother’s back for one to two weeks until they have undergone at least one molt.  The young molt several times and reach maturity in about one year.

Habits

Scorpions can be found in semi-arid regions, occupying a wide variety of habitats, from the desert floor to mountain tops.  They spend the daytime under cover of in burrows and thrive in accumulations of stones, lumber, bricks, and other debris.  At night they emerge to defend their territory and feed.  Because of their poor eyesight, scorpions lie in wait for an unsuspecting passerby rather than stalking their prey.  They generally feed on insects, spiders, millipedes and other scorpions.  They are not aggressive toward man, and only sting when handled or provoked.

During summer rains, scorpions may move in homes from nearby dry river beds (arroyos).  Since they require free water for drinking, they are attracted to air conditioners, kitchens, bathrooms, utility rooms and other areas where water is available.  Some species can survive for three to six months without food and water.

Although scorpions are found in southern states, they do not like temperatures above 32 to 38 degrees Celsius (90 to 100 degrees Fahrenheit).  When attics or similar places get hot, they move into cooler living spaces.  Due to the species’ nocturnal nature, finding sources of infestation may be difficult.

Control

Nonchemical Control

During dry weather, scorpions may be trapped by spreading wet burlap bags around the dwelling.  Accumulations of firewood, stones and other debris should be removed from the vicinity.  Tight door and window seals will help keep scorpions out of the house.  If found inside a dwelling, they can be located by using an ultraviolet (UV) or black light.  Scorpions glow brightly under UV light and can be seen from several yards away.

Chemical Applications

Since scorpions may hide for two to three months after feeding, regular pesticide applications may be necessary for effective control.

Outdoor applications of residual pesticides are essential and are aimed at eliminating scorpions in the immediate area before they gain entry into buildings.  If there are debris, ditches or other potential harborages close to buildings, the entire area should be treated, although it is not necessary to treat lawns.

Treat directly above the foundation, around windows, doorways, plumbing and conduit openings.  Also treat cracks around concrete form boards next to porches, wooden fences and weep holes in brick houses.

A thorough indoor treatment should include the cracks and crevices around baseboards, molding and kitchen cabinets.  Treat crawl spaces and attics, not used for storage, with dust formulations.

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(Courtesy of the National Pest Control Association.)