Crickets, family Gryllidae (also known as “true crickets”), are insects somewhat related to grasshoppers, and more closely related to katydids or bush crickets (family Tettigoniidae). They have somewhat flattened bodies and long antennae. There are about 900 species of crickets. They tend to be nocturnal and are often confused with grasshoppers because they have a similar body structure including jumping hind legs.
Crickets are harmless to humans, as crickets are not aggressive toward humans and rarely attack.
 Cricket chirping
Only the male crickets chirp. A large vein running along the bottom of each wing has “teeth,” much like a comb does. The chirping sound is created by running the top of one wing along the teeth at the bottom of the other wing. As he does this, the cricket also holds the wings up and open, so that the wing membranes can act as acoustical sails. It is a popular myth that the cricket chirps by rubbing its legs together.
There are four types of cricket song: The calling song attracts females and repels other males, and is fairly loud. The courting song is used when a female cricket is near, and is a very quiet song. An aggressive song is triggered by chemoreceptors on the antennae that detect the near presence of another male cricket and a copulatory song is produced for a brief period after successful deposition of sperm on the female’s eggs.
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 (approximately 62 chirps a minute at 13°C in one common species; each species has its own rate). The relationship between temperature and the rate of chirping is known as Dolbear’s Law. Using this law it is possible to calculate the temperature in Fahrenheit by adding 40 to the number of chirps produced in 14 seconds by the snowy tree cricket common in the United States.
Crickets, like all other insects, are cold-blooded. They take on the temperature of their surroundings. Many characteristics of cold-blooded animals, like the rate at which crickets chirp, or the speed at which ants walk, follow an equation called the Arrhenius equation. This equation describes the activation energy or threshold energy required to induce a chemical reaction. For instance, crickets, like all other organisms, have many chemical reactions occurring within their bodies. As the temperature rises, it becomes easier to reach a certain activation or threshold energy, and chemical reactions, like those that occur during the muscle contractions used to produce chirping, happen more rapidly. As the temperature falls, the rate of chemical reactions inside the crickets’ bodies slow down, causing characteristics, such as chirping, to also slow down.
Crickets have tympanic membranes located just below the middle joint of each front leg (or knee). This enables them to hear another cricket’s song.
In 1975, Dr. William H. Cade discovered that the parasitic tachinid fly Ormia ochracea is attracted to the song of the male cricket, and uses it to locate the male in order to deposit her larvae on him. It was the first example of a natural enemy that locates its host or prey using the mating signal. Since then, many species of crickets have been found to be carrying the same parasitic fly, or related species. In response, a mutation leaving males unable to chirp was observed amongst a population of field crickets on the Hawaiian island of Kauai.
 Diet and life cycle
Crickets are omnivores and scavengers feeding on organic materials, as well as decaying plant material, fungi, and some seedling plants. Crickets also have been known to eat their own dead when there is no other source of food available, and even exhibit predatorial behavior on other weakened or dead crickets. Crickets have relatively powerful jaws, and have been known to bite humans, mostly without breaking the skin. The bite can, however, be painful when inflicted on sensitive skin such as the webbing between fingers.
Crickets mate in late summer and lay their eggs in the fall. The eggs hatch in the spring and have been estimated to number as high as 2,000 per fertile female. Subspecies Acheta Domestica however lays eggs almost continually, with the females capable of laying at least twice a month. Female crickets have a long needlelike egg-laying organ called an ovipositor.
Crickets are popular as a live food source for carnivorous pets like frogs, lizards, tortoises, salamanders, and spiders. Feeding crickets with nutritious food in order to pass the nutrition onto animals that eat them is known as gut loading. In addition to this, the crickets are often dusted with a mineral supplement powder to ensure complete nutrition to the pet.
 In popular culture
Crickets are popular pets and are considered good luck in some countries; in China, crickets are sometimes kept in cages (Carrera 1991). It is also common to have them as caged pets in some European countries, particularly in the Iberian Peninsula. Cricket fighting as a gambling or sports betting pastime also occurs, particularly in Mexico and Southeast Asia.
The folklore and mythology surrounding crickets is extensive. The singing of crickets in the folklore of Brazil and elsewhere is sometimes taken to be a sign of impending rain, or of a financial windfall. In Álvar Núñez Cabeza de Vaca‘s chronicles of the Spanish conquest of the Americas, the sudden chirping of a cricket heralded the sighting of land for his crew, just as their water supply had run out. (Lenko and Papavero 1996). In Caraguatatuba, Brazil, a black cricket in a room is said to portend illness; a gray one, money; and a green one, hope (Lenko and Papavero 1996). In Alagoas state, northeast Brazil, a cricket announces death, thus it is killed if it chirps in a house (Araújo 1977). In the village of Capueiruçu, Bahia State, a constantly chirping cricket foretells pregnancy, but if it pauses, money is expected (K.L.G. Lima, unpublished data). The mole cricket locally known as “paquinha“, “jeguinho“, “cachorrinho-d’água“, or “cava-chão” (genera Scapteriscus and Neocurtilla, Gryllotalpidae) is said to predict rain when it digs into the ground (Fowler 1994).
In Barbados, a loud cricket means money is coming in; hence, a cricket must not be killed or evicted if it chirps inside a house. However, another type of cricket that is less noisy forebodes illness or death. (Forde 1988) In Zambia, the Gryllotalpa africanus cricket is held to bring good fortune to anyone who sees it (Mbata 1999).
Since the days of radio entertainment, the sound of crickets chirping has been consistently used as an indication that a scene is taking place late at night.
In American comedy, the sound of crickets may be used to humorously indicate a dead silence when a response or activity is expected. For example, if a comedian in a TV show tells a bad joke, instead of the audience laughing, crickets may chirp. If this happens more than once, even the crickets may be stunned into silence. Similarly on political blogs, writers may use the concept of “crickets chirping” in a rhetorical sense to signal that the writer believes that he or she has made a point that a hypothetical opponent cannot answer. The space that would have been occupied by the nonexistent answer is instead occupied by the symbolic word *crickets* or *chirp chirp* to symbolize this silence.
The Walt Disney corporation has used a number of notable cricket characters in their animated movies through the ages. Most of these characters represent good. For example, in the movie Pinocchio, Jiminy Cricket is honored with the position of the title character’s conscience. In Mulan, Cri-kee is carried in a cage as a symbol of luck, as in many Asian countries.