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Crickets, family Gryllidae (also known as "true crickets"), are insects somewhat related to grasshoppers and more closely related to katydids or bush crickets (order Orthoptera). They have somewhat flattened bodies and long antennae. Crickets are known for their chirp (which only male crickets can do; male wings have ridges or "teeth" that act like a "comb and file" instrument). The left forewing has a thick rib (a modified vein) which bears 50 to 300 minute "teeth". They chirp by raising their left forewing to a 45 degree angle and rubbing it against the upper hind edge of the right forewing, which has a thick scraper (Berenbaum 1995). This sound producing action is called "stridulation" and the song is species-specific. There are two types of cricket songs: a calling song and a courting 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. Female crickets have a long needlelike egg-laying organ (ovipositor). Crickets chirp at different rates depending both on their species and the temperature of their environment. Most species chirp at higher rates the higher the temperature is (approx. 60 chirps a minute at 13ºC 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. In fact, according to this law, it is possible to calculate the temperature in Fahrenheit by adding 39 to the number of chirps produced in 15 seconds by the snowy tree cricket common in the United States. To hear the mating call of other crickets, crickets have ears located in an unusual spot on its knees. More precisely, the ear drum is located just below the joint of their front legs. Worldwide there are about 900 known species of crickets. Crickets tend to be nocturnal and are often confused with grasshoppers, which are related but not the same, because they have a similar body structure including jumping hind legs. In 1970, 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.
Popular Culture Crickets are popular pets and are considered good luck in Asia, especially China where they are kept in cages (Carrera 1991). It is also common to have them as caged pets in some European countries, at least in the Iberian Peninsula. Cricket fighting as a blood sport has also been popular, particularly in Macao. Indeed, the folklore and mythology surrounding crickets is quite extensive and can be found in many cultures around the world. 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 Brazilian history, the sudden chirping of a cricket heralded the sighting of land for the crew of captain Álvares Nuñes Cabeza de Vaca, 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 chirps in a house (Araújo 1977). In the village of Capueiruçu, Bahia State, a cricket chirping constantly 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). A loud cricket also means money is coming in Barbados, hence no one must kill or evict the cricket if it chirps inside a house. However, another type of cricket that is less noisy forebodes illness or death. (Forde 1988). And in Zambia, the Gryllotalpa africanus cricket is held to bring good fortune to anyone who sees it (Mbata 1999). Crickets may also be eaten in some cultures, and are popular as live food for carnivorous pets. Taxonomy Subfamilies of the family Gryllidae: In addition to the above subfamilies in the family Gryllidae, several other orthopteran groups outside of this family also may be called "crickets": Image:Aust brown field cricket.jpg|Australian brown field cricket Footnotes | |||||||||||||||||||||||||||||||||
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