Why Do Crickets Stop Chirping When Approached?

There's nothing more maddening than trying to find a chirping cricket in your basement. It will sing loudly and ceaselessly until the moment you approach when it abruptly stops chirping. How does a cricket know when to hush?

Why Do Crickets Chirp?

Male crickets are the communicators of the species. The females wait for the songs of the males to spur the mating ritual. Female crickets don't chirp. Males make the chirping sound by rubbing the edges of their forewings together to call for female mates. This rubbing is called stridulation.

Some species of crickets have several songs in their repertoire. The calling song attracts females and repels other males, and it's fairly loud. This song is used only during the day in safe places; crickets aggregate at dawn without the use of acoustic calling. These groupings are typically not courtship displays or leks because they don't assemble for the sole purpose of mating.

The cricket courting song is used when a female cricket is near, and the song encourages her to mate with the caller. An aggressive song allows male crickets to interact aggressively with one another, establish territory, and claim access to females in that territory. A triumphal song is produced for a brief period after mating and may reinforce the mating bond to encourage the female to lay eggs rather than find another male.

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Mapping Cricket Chirping

The different songs used by crickets are subtle, but they do vary in pulse numbers and hertzes, or frequency. Chirp songs have one to eight pulses, spaced at regular intervals. Compared with aggressive songs, courtship chirps tend to have more pulses and shorter intervals between them.

Crickets chirp at different rates depending on their species and the temperature of their environment. Most species chirp at higher rates the higher the temperature is. The relationship between temperature and the rate of chirping is known as Dolbear's law. According to this law, counting the number of chirps produced in 14 seconds by the snowy tree cricket, common in the United States, and adding 40 will approximate the temperature in degrees Fahrenheit.

Crickets "Hear" Vibrations

Crickets know when we approach because they are sensitive to vibrations and noises. Since most predators are active during daylight, crickets chirp at night. The slightest vibration might mean an approaching threat, so the cricket goes quiet to throw the predator off its trail.

Crickets don't have ears like we do. Instead, they have a pair of tympanal organs on their forewings (tegmina), which vibrate in response to vibrating molecules (sound to humans) in the surrounding air. A special receptor called the chordotonal organ translates the vibration from the tympanal organ into a nerve impulse, which reaches the cricket's brain.

Crickets are extremely sensitive to vibration. No matter how soft or quiet you try to be, a cricket will get a warning nerve impulse. Humans hear something first, but crickets always feel it.

A cricket is always on the alert for predators. Its body color, usually brown or black, blends in with most of its environments. But when it feels vibrations, it responds to the nerve impulse by doing what it can to hide—it goes silent.

How to Sneak Up on a Cricket

If you're patient, you can sneak up on a chirping cricket. Each time you move, it will stop chirping. If you remain still, eventually it will decide it's safe and begin calling again. Keep following the sound, stopping each time it goes silent, and you'll eventually find your cricket.

Sources

• Boake, Christine R.B. "Natural History and Acoustic Behavior of a Gregarious Cricket." Behaviour.
• Darling, Ruth A. "A Directed Research Project Investigating Territoriality & Aggression in Crickets." The American Biology Teacher.
• Doherty, John, and Hoy, Ronald. "The Auditory Behavior of Crickets: Some Views of Genetic Coupling, Song Recognition, and Predator Detection." The Quarterly Review of Biology.
• Hoffart, Cara; Jones, Kylie; and Hill, Peggy S.M. "Comparative Morphology of the Stridulatory Apparatus of the Gryllotalpidae (Orthoptera) of the Continental United States." Journal of the Kansas Entomological Society.