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Friday, Oct. 19, 2001
By ROWAN HOOPER
* Japanese name:Tonosamabatta * Scientific name: Locusta migratoria * Description: Locusts are large, sturdy grasshoppers but have more advanced powers of flight than most. Females are larger than males, with a body length of about 50 mm, compared to the males' average 35 mm. Locusts are cryptically colored, either brown or green. Like most grasshoppers, they can "sing." They do this by rubbing their hind legs against a hardened vein on their forewing. Their ears are located on the abdomen. * Where to find them: From Hokkaido to Okinawa, adults can be seen from July to October. In late spring and summer, females lay pods of 40-50 eggs up to 10 cm underground. If temperatures are high, the eggs hatch in about two weeks. Locust nymphs look like small adults, without wings. They grow through five instars, or stages, in about four weeks, before becoming adults. * Food: Almost anything green. Crops, grass and low bushes. Locusts can be serious pests, destroying huge amounts of vegetation. * Special features: Migratory locusts can exist in one of two modes, known as the solitary phase and the migratory/gregarious phase. The ability to change phase is central to the locust's notorious reputation as a pest. In response to increases in population density, locusts change from the solitary life, where they avoid each other, to the migratory phase, where they actively aggregate (group together). In this phase, they can move many kilometers in one day, sometimes forming huge swarms that show up on radar. Massive swarms are often seen in North Africa, the Middle East and Australia, but sometimes in Japan, too. In 1986, in Kagoshima Prefecture, a swarm of around 30 million locusts devastated land in a huge swath, moving with wind currents and eating everything in their path. The solitary phase can be distinguished from the migratory phase by the presence of a distinct bump on the pronotum -- the protective shield behind the head.