CHILD'S FACE: CHARACTERISTICS, HABITAT, REPRODUCTION, FEEDING - BIOLOGY - 2025

Child's face (Stenopelmatus coahuilensis) is an orthoptera of the Stenopelmatidae family, native to the Coachella Valley in California. In the United States, pinholes are commonly called "sand crickets," "stone crickets," "potato bugs," "skull bugs," and more commonly "Jerusalem crickets."

Unlike what its name suggests, this animal is not a cricket (family Gryllidae) and it does not come from Jerusalem either. Initially it was believed that the name "Jerusalem cricket" was because of the similarity of the insect in resting position to the Jerusalem cross, an angled cross with short bars towards the ends.

Source: Greg Schechter from San Francisco, USA

However, its name seems to derive from a word used by young people to express astonishment at a natural phenomenon, to which they shouted: Jerusalem! In Spanish, it receives the name of "face of a child" given the resemblance of its face to that of a human.

The S. coahuilensis adult is wingless, has a robust body and can measure 3-5 cm in length. Its head and jaw are large, as are its hind legs. The body is bright brown with black bands on its abdomen.

They are nocturnal and spend much of their lives underground. They manage to perceive low-frequency vibrations with the subgenual organs, located in their legs. With their abdomen they cause a certain drumming and, in this way, obtain location and distance information.

Generally, only one generation is observed per year. Females live twice as long as males, since they usually eat it during mating. The male remains immobile while the female devours him.

They are mistakenly believed to be poisonous insects and, in some places, tend to kill themselves. Since 1996, the species has entered the red list under the Vulnerable category.

characteristics

The adult reaches a size of 3 to 5 centimeters in length. Its body is robust, bright pale brown in color. On the dorsal part of the abdomen it has broad dark brown bands and, on the ventral part, these bands are paler, thinner and almost imperceptible. They are wingless, that is, they lack wings. They also do not have eardrums or any auditory organ.

The head is large similar to that of a human, hence its name in Spanish "face of a child." The vertex of the posterior tibia is surrounded by large spines. The femurs and tibiae are thickened, especially towards the hind legs.

They are hemimetabolic insects, that is, they go through three stages of development: egg, nymph and adult or imago. An individual goes through 11 molting changes during growth, completing its development at approximately 18 months.

Adult females are distinguished by a darkened sclerotic ovipositor (on the tips and ventral surfaces). The males, on the other hand, have a pair of curved, black, sclerotic hooks located in the middle of each fence.

The hooks of adult males develop gradually, from small ridges barely visible at earlier instants. These hooks are used during mating as an anchoring organ during copulation.

The eggs are about 3mm long, oval in shape and yellowish-white in color.

Habitat and distribution

This species lives in most of the available habitats, between grasslands, chaparral, and sand dunes. Some individuals are usually found under rocks or in loose soil.

The species S. coahuilensis is endemic to the United States, specifically the Coachella Valley in California. This species is absent in fresh and salt water habitats, and in desert areas of high alkalinity or salinity.

Reproduction

The female lays eggs in groups of 15 to 25 underground shortly after mating. It is not known with certainty if the eggs go through a period of diapause (inactivity); despite this, they hatch between the fall and spring season.

Usually only one generation is observed per year. During mating, the female usually devours the male; for that reason, the female lives for 6 to 12 months and the males only half that time. Intercourse can take hours. The male incites the female to eat it alive, where it remains immobile while the female consumes it.

At the beginning of copulation, the male holds the female's hind tibia, while the female faces each other in the opposite direction. The female then places her hind legs close to the subgenital plate and is held by the male's hooks.

Feeding

The Jerusalem cricket feeds on small arthropods, insects, dead organic matter, and other small animals. With their jaw, they usually excavate and form small tunnels so that in this way, they can consume tubers and roots.

They become beneficial insects, as they favor the growth of plants. During excavation, the insect removes the soil, contributing to the aeration of the soil.

In laboratory conditions, the child's face is nourished with lettuce (to obtain water), dehydrated food for rabbits and cats, along with oat flakes.

Behavior

It is a kind of nocturnal habits. She usually looks for a partner and food at night; in the day, he is in charge of seeking refuge. For this reason, they can be observed during dawn or towards dusk, making them easy prey for different predators, such as foxes, skunks, owls, rodents, snakes and scorpions.

Since they spend much of their lives underground, their visual and auditory perception is limited; Despite this, the subgenual organs located in their legs serve as tactile organs capable of receiving low frequency vibrations, used to obtain information on location, distance and, sometimes, sex.

Communication

The terrestrial transmission of impulses is produced by the abdomen, which hits the ground repeatedly producing a percussion wave, also called drums. Each species has a distinctive percussion sound. Both sexes of all species drum spontaneously, sometimes producing audible sounds at 20 meters.

"Call" drums vary in complexity between species, ranging from a series of individual beats at rates of 0.5 to 15 drums per second, to groupings of beats with speeds approaching 40 drums per second.

Adult males produce "sex clarification" drums, and they occur only in species where the male and female have the same call drum, and one sex cannot tell who they are responding to. This strategy also allows males to distinguish themselves from other males. These drums are fast and very strong.

There are also the "courtship" drums, percussion that consists of short series of non-audible abdominal blows or tremors (the abdomen does not make contact with the surface) at a rate of 2 to 4 per second. In general, males are the ones that perform these vibrations when they are at a short distance (approximately 6 cm) from the female.

There are also so-called "nymphal" drums, which have the same pattern as the drum made by adults, however, they are produced less frequently. While the speed of the drums appears to be unrelated to the size of the body, it may be related to the consistency and / or density of the substrate.

Defending

Unlike true crickets that use their wings to make sounds, the species S. coahuilensis rubs its hind legs against the sides of the abdomen, producing a harsh, cutting noise called stridulation. This serves as a defense mechanism against its predators.

Another defense mechanism employed by Jerusalem crickets is the anal excretion of a foul-smelling substance. They do not have poisonous glands, but their bite can be painful.

Bibliographic references

1. Stenopelmatus. Taken from Wikipedia.org
2. Jerusalem cricket. Taken from Wikipedia.org
3. Jerusalem cricket. Taken from Wikipedia. Org
4. Stenopelmatus coahuilensis. Taken from IT IS.gov.
5. Weissman, D. Jerusalem! Cricket? (Orthoptera: Stenopelmatidae: Stenopelmatus); Origins of a Common Name. 2005 American Entomologist 51 (3): 138-139.
6. Stenopelmatus coahuilensis, Coachella Valley Jerusalem Cricket. Taken from iucnredlist.org
7. Capinera, J (2008). Encyclopedia of Entomology. University of Florida. Springer.
8. Robinson, W (2005). Urban insects and arachnids. Cambridge. New York, United States: 3-456