Night singers with ovipositors star from Pinocchio to Dickens
Crickets, the superfamily Grylloidea, live everywhere except the cold lands beyond about 55 degrees of latitude. Males sing by rasping one leathery forewing against the other, and in one common species the chirp rate climbs so steadily with heat that it works as a rough thermometer.
Crickets are orthopterans, related to bush crickets and more distantly to grasshoppers. They have rounded heads, long antennae, three simple eyes on the forehead, and hind legs with swollen thighs for jumping; females carry a long, needle-like ovipositor. The biggest, the bull crickets, reach 5 cm and dig burrows a metre deep. Many species cannot fly, and some shed or even eat their hind wings after dispersing. Diversity peaks in the tropics: 88 species were heard singing at one spot near Kuala Lumpur.
Only males sing. A toothed file on one forewing scrapes a ridge on the other, and a membrane called the harp amplifies the sound, which females hear through eardrums on their front legs. Species have calling, courting, aggressive, and even triumphal songs after mating. Chirping speeds up with warmth, a pattern called Dolbear’s law: count a snowy tree cricket’s chirps in 14 seconds, add 40, and you get the Fahrenheit temperature.
Song has a cost. In 1975 William Cade found that a parasitic fly homes in on male calls to drop its larvae on them. On the Hawaiian island of Kauai, a mutation left males silent and safer, and a separate mutation did the same on Oahu; newer purring males there attract females while drawing fewer flies.
Rival males lash antennae and grapple until the winner sings and the loser falls quiet. Crickets appear in Pinocchio, Dickens’s The Cricket on the Hearth, and The Cricket in Times Square, are kept for fighting from China to Europe, and are sold deep-fried as snacks in Southeast Asia.
Source: Cricket (insect)
