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Grasshoppers are insects of the order Orthoptera, suborder Caelifera. They are sometimes referred to as short-horned grasshoppers to distinguish them from the katydids (bush crickets) which have much longer antennae. They are typically ground-dwelling insects with powerful hind legs which enable them to escape from threats by leaping vigorously. They are hemimetabolous insects (do not undergo complete metamorphosis) which hatch from an egg into a nymph or "hopper" which undergoes five moults, becoming more similar to the adult insect at each developmental stage. At high population densities and under certain environmental conditions, some grasshopper species can change colour and behaviour and form swarms. Under these circumstances they are known as locusts. Grasshoppers are plant-eaters, sometimes becoming serious pests of cereals, vegetables and pasture, especially when they swarm in their millions as locusts and destroy crops over wide areas. They protect themselves from predators by camouflage; when detected, many species attempt to startle the predator with a brilliantly-coloured wing-flash while jumping and (if adult) launching themselves into the air, usually flying for only a short distance. Other species such as the rainbow grasshopper have warning coloration which deters predators. Grasshoppers are affected by parasites and various diseases, and many predatory creatures feed on both nymphs and adults. The eggs are the subject of attack by parasitoids and predators. Grasshoppers have had a long relationship with humans. Swarms of locusts have had dramatic effects that have changed the course of history, and even in smaller numbers grasshoppers can be serious pests. They are eaten as food and also feature in art, symbolism and literature. ==Characteristics== Grasshoppers have the typical insect body plan of head, thorax and abdomen. The head is held vertically, at an angle to the body with the mouth at the bottom. It bears a large pair of compound eyes which give all-round vision, three simple eyes which can detect light and dark and a pair of thread-like antennae which are sensitive to touch and smell. The downward-directed mouthparts are modified for chewing and there are two sensory palps in front of the jaws.〔 The thorax and abdomen are segmented and have a rigid cuticle made up of overlapping plates composed of chitin. The three fused thoracic segments bear three pairs of legs and two pairs of wings. The forewings, known as tegmina, are narrow and leathery while the hind wings are large and membranous, the veins providing strength. The legs are terminated by claws for gripping. The hind leg is particularly powerful; the femur is robust and has several ridges where different surfaces join and the inner ridges bear stridulatory pegs in some species. The posterior edge of the tibia bears a double row of spines and there are a pair of articulated spurs near its lower end. The interior of the thorax houses the muscles that control the limbs. The abdomen has eleven segments, the first of which is fused to the thorax and contains the auditory organ and tympanum. Segments two to eight are ring-shaped and joined by flexible membranes. Segments nine to eleven are reduced; segment nine bears a pair of cerci and segments ten and eleven house the reproductive organs. Female grasshoppers are normally larger than males, with short ovipositors.〔 The name "Caelifera" comes from the Latin and means ''chisel-bearing'', referring to the sharp ovipositor. Those species that make easily heard noises usually do so by rubbing a row of pegs on the hind femurs against the edges of the forewings (stridulation). These sounds are produced mainly by males to attract females, though in some species the females also stridulate.〔(【引用サイトリンク】url=http://australianmuseum.net.au/grasshoppers-crickets-katydids-and-locusts-order-orthoptera )〕 Grasshoppers are easily confused with the other sub-order of Orthoptera, Ensifera (crickets), but differ in many aspects, such as the number of segments in their antennae and structure of the ovipositor, as well as the location of the tympana and modes of sound production. Ensiferans have antennae that can be much longer than the body and have at least 20–24 segments, while caeliferans have fewer segments in their shorter, stouter antennae.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「grasshopper」の詳細全文を読む スポンサード リンク
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