Senchikogane - Senchikogane

This insect belongs to the family Geotrupidae of the order Coleoptera in the class Insecta. It is found throughout Japan, as well as the Kuril Islands, the Korean Peninsula, China, and eastern Siberia. Its body length is 14 to 20 millimeters. It is oval in shape with a bulging back, and its body surface has a metallic luster of colours such as purple copper, golden copper, blue-and-blue, and green copper, and its head is flat and semicircular. Adults gather on animal dung and animal carcasses, hiding in deep holes dug under or near the dung. Females stuff the holes with dung and lay eggs, which the larvae feed on and grow.

There are over 500 known species of Geotrupidae in the world, but six species have been recorded in Japan. They can be distinguished from other types of scarab beetles by the fact that they have 11 antennae and six abdominal segments, as well as the shape of their body and head. Some species of this group are known overseas to feed on mushrooms and humus. The Japanese Geotrupidae beetle, G. auratus , is slightly different from the Geotrupidae in that it has a beautiful metallic color such as red, reddish purple, blue-indigo, or green, and a slightly trapezoidal head. It mainly gathers in mountainous areas to feed on dung. The red-breasted Geotrupidae, Bolbocerosoma nigroplagiatum , has a nearly circular body with black markings on a reddish-brown background, and flies to lights.

[Takehiko Nakane]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

昆虫綱甲虫目センチコガネ科に属する昆虫。日本各地のほか千島列島、朝鮮半島、中国、東シベリアなどに分布する。体長14～20ミリメートル。楕円(だえん)形で背面は膨らみ、体表には紫銅、金銅、青藍(せいらん)、緑銅など金属光沢の色彩をもち、頭は平たくて半円形である。成虫は獣糞(じゅうふん)や動物の死体に集まり、糞の下や近くに深く孔(あな)を掘って隠れる。雌は糞を孔に詰めて産卵し、幼虫はこれを食べて成育する。

　センチコガネ科Geotrupidaeは、世界に500種以上知られているが、日本産は6種が記録されている。コガネムシの他の類とは、触角が11節で腹節が6節であることや、体・頭の形で区別できる。この類のなかにはキノコや腐植質などを食べる種類も海外には知られている。日本産のオオセンチコガネG. auratusは、赤、赤紫、青藍、緑など美しい金属色で頭形がやや台形でセンチコガネとすこし違い、おもに山地で糞に集まる。ムネアカセンチコガネBolbocerosoma nigroplagiatumは、体が円形に近く、赤褐色の地に黒紋があり、灯火に飛んでくる。

［中根猛彦］

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