By MARY K. HANSON/Tuleyome
Imagine a humpbacked insect with opposable “thumbs” on its front legs, “meat hooks” on its hind legs, limbs that can regrow after being removed, and crushing mouth parts that can inflict a bite so painful you’d think you’d been poisoned by it… No, it’s not an alien or something from a nightmare, it’s a very real insect: the Jerusalem Cricket (Stenopelmatus sp.).
Native to Mexico and the western United States, the Jerusalem Cricket looks something like a giant mutant ant, with a vaguely human head and dark multi-faceted eyes. Although they appear like something out of a horror movie, these insects – which are not crickets and don’t hail from Jerusalem — are actually fairly benign.
It’s thought that their name stems from the early 1900’s when the exclamation “Oh, Jerusalem!” was commonly used to express feelings of astonishment or disgust. They’re also referred to as “Red-Skulls,” “Children of the Earth,” and more commonly as “Potato Bugs.”
Although the name “Potato Bug” was derived from the notion that these insect eat tubers, like potatoes, that’s only partially true. Jerusalem Crickets do eat roots and tubers, but usually only those of plants that are either already dead or dying. They’re one of Nature’s recyclers. They’ll even eat their own shed skin between each molt. Other insects — living or dead — are also added to their diet to provide them with more nourishment.
The Jerusalem Crickets have no wings, so they are earthbound, and on the surface of the earth they are actually rather slow and clumsy in their movements. It’s underground where the Jerusalem Cricket is most comfortable and most adept. Its specialized feet are used mostly for burrowing through the soft earth and under rocks and the roots of trees. It actually spends the majority of its time underground, but is often found on the surface after a hard rain when its burrows get flooded. Once above ground, these insects are easy-pickings for predators.
As mentioned, the Jerusalem Cricket packs a hard bite, but it’s not venomous. When a bite won’t stave off an attack, the Jerusalem Cricket will “skunk” an aggressor with a foul-smelling odor.
They don’t vocalize much, although they can hiss by expelling air through the spiracles on their bodies. Without wings, the “crickets” cannot produce sound as some other insects can, nor can they hear, so they communicate with one another by drumming their abdomen against the ground.
It’s believed that different species of Jerusalem Cricket create different drumming songs to attract their mates. The drumming that one Jerusalem Cricket produces is picked up by other Jerusalem Crickets through special sensors on their legs called “subgenual” (Latin for “below the knee”) organs. Other insects, like cockroaches, have similar organs, but the organs’ shape and sensitivity varies by insect.
Male Jerusalem Crickets can be distinguished from the females by the black “hooks” that appear between the cerci at the end of the abdomen. The cerci are those short fingerling-looking things that protrude from the last segment of the abdomen. In lieu of the black hooks, female Jerusalem Crickets will have a long ovipositor below the cerci.
During the mating season, the Jerusalem Crickets are vulnerable to predation since their drumming requires that they be above ground. Another danger to the males during this time is the fact that the females will often attack and eat their suitors immediately after mating.
Once they have been fertilized, the female will lay her eggs in the ground, usually a few inches from the surface, and abandon them there. After the eggs hatch, it takes about two years for the young “crickets” to reach their full size and sexual maturity. During those two years, they go through about 12 molts, growing larger after each one until they’re about two inches long. A growing Jerusalem Cricket can re-grow a lost limb during the next successive molt after it’s injured, in much the same way some crabs can regrow a lost claw.
Although these weird-looking insects may seem like the stuff of science fiction, they’re actually an integral part of the environment. Their burrowing helps to aerate the soil, they’re eating helps to process organic matter, and their bodies add nutrition to the diet of birds, bats, coyotes, foxes and other animals. So, they may be creepy-looking, but they do their jobs well.
Mary K. Hanson is a Certified California Naturalist, author and nature photographer. Tuleyome is a 501(c)(3) nonprofit conservation organization based in Woodland, CA. For more information, see their website at: www.tuleyome.org.