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''Callosobruchus maculatus'' is a species of beetle known commonly as the cowpea weevil or cowpea seed beetle.〔Tran, B. M. D. and P. F. Credland. (1995). (Consequences of inbreeding for the cowpea seed beetle, ''Callosobruchus maculatus'' (F.) (Coleoptera: Bruchidae). ) ''Biological Journal of the Linnean Society'' 56 483-503.〕 It is a member of the leaf beetle family, Chrysomelidae, and not a true weevil. This common pest of stored legumes has a cosmopolitan distribution, occurring on every continent except Antarctica.〔(Cowpea weevil (''Callosobruchus maculatus'' (Fabricius, 1775)). ) PaDIL.〕 The beetle most likely originated in West Africa and moved around the globe with the trade of legumes and other crops.〔 As only a small number of individuals were likely present in legumes carried by people to distant places, the populations that have invaded various parts of the globe have likely gone through multiple bottlenecks. Despite these bottlenecks and the subsequent rounds of inbreeding, these populations persist. This ability to withstand a high degree of inbreeding has likely contributed to this species’ prevalence as a pest.〔 It is used as a model organism for both research and education due to its quick generation time, sexual dimorphism, and ease of maintenance.〔(Bean Beetles: A Model Organism for Inquiry-based Undergraduate Laboratories. ) beanbeetles.org, Emory University and Morehouse College.〕 ==Description== The cowpea weevil lacks the "snout" of a true weevil. It is more elongated in shape than other members of the leaf beetle family. It is reddish-brown overall, with black and gray elytra marked with two central black spots. The last segment of the abdomen extends out from under the short elytra, and also has two black spots.〔(Cowpea weevil. ) Texas A&M AgriLife Extension.〕 The beetle is sexually dimorphic and males are easily distinguished from females. The females are sometimes larger than males, but this is not true of all strains. Females are darker overall, while males are brown. The plate covering the end of the abdomen is large and dark in color along the sides in females, and smaller without the dark areas in males.〔(A Handbook on Bean Beetles, ''Callosobruchus maculatus''. ) beanbeetles.org, Emory University and Morehouse College.〕 There are two morphs of ''C. maculatus'', a flightless form and a flying form. The flying form is more common in beetles that developed in conditions of high larval density and high temperatures. The flying form has a longer lifespan and lower fecundity, and the sexes are less dimorphic and can be more difficult to tell apart.〔 The egg is clear, shiny, oval to spindle-shaped, and about 0.75 millimeters long.〔 The larva is whitish in color.〔 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「Callosobruchus maculatus」の詳細全文を読む スポンサード リンク
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