Jerusalem Crickets, Family Stenopelmatidae

Seeing a Jerusalem cricket for the first time can be an unsettling experience, even to those who aren't prone to entomophobia. They look somewhat like giant, muscular ants with humanoid heads and dark, beady eyes. Although Jerusalem crickets (family Stenopelmatidae) are indeed quite large, they're generally harmless. We know relatively little about their life history, and many species remain unnamed and undescribed.

What Jerusalem Crickets Look Like

Did you ever play the board game Cootie as a child? Imagine turning over a rock, and finding a Cootie come to life, staring up at you with a menacing expression! That's how people often discover their first Jerusalem cricket, so it's no surprise that these insects have earned many nicknames, none of them particularly endearing. In the 19th century, people used the expression "Jerusalem!" as an expletive, and that's believed to be the origin of the common name.

People also believed (incorrectly) that these odd insects with human faces were highly venomous and potentially lethal, so they were given nicknames rife with superstition and fear: skull insects, bone neck beetles, old bald-headed man, face of a child, and child of the Earth (Niño de la Tierra in Spanish-speaking cultures). In California, they're most often called potato bugs, for their habit of nibbling on potato plants. In entomology circles, they're also called sand crickets or stone crickets.

Jerusalem crickets range in length from a respectable 2 cm to an impressive 7.5 cm (about 3 inches) and can weigh as much as 13 g. Most of these flightless crickets are brown or tan in color but have a striped abdomen with alternating bands of black and light brown. They're quite plump, with robust abdomens and large, round heads. Jerusalem crickets lack venom glands, but they do have powerful jaws and can inflict a painful bite if mishandled. Some species in Central America and Mexico can jump to flee from danger.

When they reach sexual maturity (adulthood), males can be differentiated by females by the presence of a pair of black hooks at the tip of the abdomen, between the cerci. On an adult female, you'll find the ovipositor, which is darker on the underside and located below the cerci.

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How Jerusalem Crickets Are Classified

• Kingdom – Animalia
• Phylum – Arthropoda
• Class – Insecta
• Order – Orthoptera
• Family - Stenopelmatidae

What Jerusalem Crickets Eat

Jerusalem crickets feed on organic matter in the soil, both living and dead. Some may scavenge, while others are thought to hunt other arthropods. Jerusalem crickets also practice cannibalism on occasion, particularly when confined together in captivity. Females will often eat their male partners after consummating the relationship (much like the sexual cannibalism of female praying mantids, which is better known).

The Life Cycle of Jerusalem Crickets 

Like all of the Orthoptera, Jerusalem crickets undergo incomplete or simple metamorphosis. The mated female oviposits eggs a few inches deep in the soil. Young nymphs usually appear in the fall, less often in the spring. After molting, the nymph eats the cast skin to recycle its precious minerals. Jerusalem crickets require perhaps a dozen molts, and almost two full years to reach adulthood. In some species or climates, they may need up to three years to complete the life cycle.

Special Behaviors of Jerusalem Crickets 

Jerusalem crickets will wave their spiny hind legs in the air to repel any perceived threats. Their concern is not without merit, because most predators can't resist such a fat, easy-to-catch insect. They are an important source of nutrition for bats, skunks, foxes, coyotes, and other animals. Should a predator manage to yank its leg loose, the Jerusalem cricket nymph can regenerate the missing limb over successive molts.

During courtship, both male and female Jerusalem crickets drum their abdomens to call receptive mates. The sound travels through the soil and can be heard via special auditory organs on the cricket's legs.

Where Jerusalem Crickets Live

In the U.S., Jerusalem crickets inhabit western states, especially those along the Pacific Coast. Members of the family Stenopelmatidae are also well established in Mexico and Central America and are sometimes found as far north as British Columbia. They seem to prefer habitats with damp, sandy soils, but can be found from coastal dunes to cloud forests. Some species are restricted to such limited dune systems that they may warrant special protection, lest their habitat be adversely impacted by human activities.

_Sources:

• _{Jerusalem Crickets (Orthoptera, Stenopelmatidae), by David B. Weissman, Amy G. Vandergast, and Norihimo Ueshima. From Encyclopedia of Entomology, edited by John L. Capinera.}
• _{Borror and DeLong's Introduction to the Study of Insects, 7th edition, by Charles A. Triplehorn and Norman F. Johnson.}
• _{BACKYARD MONSTERS? NOPE, JERUSALEM CRICKETS!, by Arthur V. Evans, What's Bugging You?. Accessed March 4, 2013.}
• _{Family Stenopelmatidae - Jerusalem Crickets, Bugguide.net. Accessed March 4, 2013.}
• _{Jerusalem Crickets, California Academy of Sciences. Accessed March 4, 2013.}
• _{Jerusalem Cricket, San Diego Museum of Natural History. Accessed March 4, 2013.}