Jerusalem crickets, often called potato bugs or niño de la tierra, are large, distinctive insects that frequently cause alarm due to their size and appearance. The primary concern is whether they pose a threat. While these insects possess mandibles capable of biting human skin, they only do so under specific, rare circumstances, and the bite is not medically significant.
Identification and Common Misconceptions
The Jerusalem cricket is a large, flightless insect that can grow up to two or three inches in length, and is characterized by a stout, wingless body. Its most recognizable feature is its disproportionately large, smooth, bulbous head, often described as human-like or baby-faced, which is typically pale yellow or orange-yellow in color. The abdomen is robust and usually displays distinct black and yellowish-brown banding.
Despite their common name, these creatures are not true crickets (family Gryllidae). They are classified in the family Stenopelmatidae, belonging to the genus Stenopelmatus or Ammopelmatus. Their taxonomy places them in a group related to wetas and king crickets. The nickname “potato bug” comes from their tendency to feed on tubers and roots, though they are primarily nocturnal scavengers.
These insects are native to the Western United States, Mexico, and parts of Central America. They spend the majority of their lives underground, burrowing in moist, loose soil beneath rocks, logs, or debris. Their powerful, spiny legs are adapted for this fossorial, or burrowing, lifestyle. They are rarely seen during the day, which contributes to the alarm when they are accidentally unearthed.
The Truth About Biting
Jerusalem crickets possess strong mandibles, which they use for feeding on decaying organic matter and roots. These mouthparts are powerful enough to cut through plant material and break human skin. However, biting is strictly a defensive behavior, not an act of aggression toward humans. The insect only attempts to bite when severely threatened, such as when roughly handled or grabbed.
When disturbed, the cricket’s first instinct is usually to flee or, if cornered, to assume a defensive posture. In this stance, it may flip onto its back, snap its mandibles, and kick its hind legs to startle a predator. A bite is the last resort for self-defense, contrasting with predatory insects that bite to inject venom or secure prey.
The likelihood of a bite increases if a person attempts to pick up the insect with bare hands. Some individuals may play dead before resorting to biting if handling continues or becomes rough. Because the jaws are strong, they have been known to cut through thin plastic or fabric if trapped. The mechanical force of the bite causes the pain.
Are They Venomous or Dangerous
Jerusalem crickets are not venomous and do not produce or inject any toxins. The pain from the bite is purely mechanical, caused by the force of the mandibles clamping down on the skin. Unlike spiders or scorpions, these insects do not possess venom glands or stingers.
A bite typically results in localized, moderate pain, similar to a strong pinch, and may cause minor swelling or redness if the skin is broken. The discomfort is short-lived and resolves quickly without complication. The primary risk is the potential for a secondary bacterial infection if the small wound is not properly cleaned.
They do not transmit diseases to humans. The notion that their bite is dangerous may stem from their alarming appearance or folklore. While a remote possibility exists for a person to have an allergic reaction to any insect bite, this is extremely rare for the Jerusalem cricket and is an individual sensitivity, not a result of any inherent venom. For the vast majority of people, the encounter is generally more startling than harmful.
Safe Handling and Prevention
If a Jerusalem cricket is encountered, the safest approach is to avoid handling it. They are docile by nature and prefer to escape rather than engage in conflict. If one is found inside a home, it can be safely and humanely removed.
The insect can be swept gently into a dustpan or container and released outside. It is best to release them in a sheltered area, such as under a log or in a garden bed. Because Jerusalem crickets are beneficial to the ecosystem, acting as decomposers by consuming decaying organic matter, leaving them alone is the best practice.
To prevent them from entering living spaces, homeowners should focus on reducing moisture and removing hiding places near the foundation. This includes sealing cracks and gaps in the foundation and around doors and windows, as well as clearing away debris like leaf piles, rocks, and boards. Removing excess mulch and improving drainage will also help, as they are drawn to damp environments. These simple preventative measures minimize the chance of an accidental encounter.