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Beetles are a group of insects that form the order Coleoptera . The word "coleoptera" is from the Greek , ''koleos'', meaning "sheath"; and , ''pteron'', meaning "wing", thus "sheathed wing", because most beetles have two pairs of wings, the front pair, the "elytra", being hardened and thickened into a shell-like protection for the rear pair and the beetle's abdomen. ==Overview== The Coleopterans include more species than any other order, constituting almost 25% of all known types of animal life-forms.〔Powell (2009)〕 About 40% of all described insect species are beetles (about 400,000 species〔Hammond, P. M. (1992). ("Species inventory" ), pp. 17–39 in ''Global Biodiversity, Status of the Earth’s Living Resources'', B. Groombridge, ed. Chapman and Hall, London, ISBN 0412472406.〕), and new species are discovered frequently. Some estimates put the total number of species, described and undescribed, at as high as 100 million, but a figure of one million is more widely accepted. The largest taxonomic family is commonly thought to be Curculionidae (the weevils or snout beetles), but recently the Staphylinidae (the rove beetles) have claimed this title. The diversity of beetles is very wide. They are found in all major habitats, except marine and the polar regions. They have many classes of ecological effects; particular species are adapted to practically every kind of diet. Some are nonspecialist detritus feeders, breaking down animal and plant debris; some feed on particular kinds of carrion such as flesh or hide; some feed on wastes such as dung; some feed on fungi, some on particular species of plants, others on a wide range of plants. Some are generalist pollen, flower and fruit eaters. Some are predatory, usually on other invertebrates; some are parasites or parasitoids. Many of the predatory species are important controls of agricultural pests. For example, beetles in the family Coccinellidae ("ladybirds" or "ladybugs") consume aphids, scale insects, thrips, and other insects that damage crops. Conversely, beetles are prey of numerous invertebrates and vertebrates, including other insects, arachnids, fish, amphibians, reptiles, birds, and mammals. Coleopterans are not generally serious pests, but they include agricultural and industrial pests, such as the Colorado potato beetle ''Leptinotarsa decemlineata'', the boll weevil ''Anthonomus grandis'', the red flour beetle ''Tribolium castaneum'', and the mungbean or cowpea beetle ''Callosobruchus maculatus''. Also included is the death-watch beetle, the larvae of which can cause serious structural damage to buildings by boring into the timbers. All beetles have a hard exoskeleton, particularly on their forewings (elytra, singular elytron). These elytra distinguish beetles from most other insect species, except for the Dermaptera. The hemelytra of Heteroptera have a slight resemblance, but are not the same and their function is largely different. Like all armored insects, beetles' exoskeletons comprise numerous plates called sclerites, some fused, and some separated by thin sutures. This combines armored defenses with maintained flexibility. The general anatomy of a beetle is superficially uniform, but specific organs and appendages may vary greatly in appearance and function between the many families in the order, and even more so between the suborders (such as Adephaga) that currently seem increasingly to be separate orders in their own right. All insects' bodies are divided into three sections: the head, the thorax, and the abdomen, and the Coleopterans are no exception. Their internal morphology and physiology also resemble those of other insects. Beetles are endopterygotes; they undergo complete metamorphosis, a biological process by which an animal physically develops after a birth or hatching, undergoing a series of conspicuous and relatively abrupt changes in its body structure. Males may fight for females in various ways, and such species tend to display marked sexual dimorphism. 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「beetle」の詳細全文を読む スポンサード リンク
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