Mealworm - Garbage Beetle

An insect belonging to the family Tenebrionidae in the order Coleoptera of the class Insecta. It is found throughout Japan, as well as in Siberia, Europe, and North America, and is counted as a pest of stored grain, but does little damage. Its body length is about 15 mm. It is black-brown and elongated, with a slightly wider rear. It appears from June to July and can be found on rotting wood, as well as in warehouses and barns. The larvae are thin, cylindrical, and black-brown in color, and both adult larvae feed on grain waste.

Darkling beetles (Tenebrionidae) are widely distributed throughout the world, especially in tropical regions. Over 15,000 species are known, with over 200 recorded in Japan. They are about 2-35 mm long. Their shapes are extremely varied, and it is said that there are species that resemble any other beetle. Generally speaking, most species are black, but there are also many other species, such as the rainbow beetle, which has a metallic rainbow sheen, and the monkey beetle, which has red markings. Shapes also vary from hemispherical like the ladybug beetle, to egg-shaped, oval-shaped, cylindrical, and sometimes gourd-shaped like the aspen beetle. The antennae gradually become wider towards the tip, the base of the forelegs is closed at the rear, the tarsus has five segments while the hind legs have four segments, and the claws are simple.

There are no species in Japan that are found in deserts and barren lands overseas, but there are many beetles such as the Japanese mealworm, Japanese giant mealworm, and red mealworm that live on dead and rotting wood, as well as stag beetle, long rainbow mealworm, mushroom mealworm, and horned mealworm that gather on mushrooms, and ladybug mealworms that eat moss. There are also sand mealworms that are common on beaches and riverbanks, and seashore mealworms such as the Japanese mealworm, bone mealworm, and sea shore mealworm that live on coasts. In addition, many species that infest stored grains are common worldwide or have a wide distribution range, and there are many in Japan such as the rice mealworm and red flour beetle, and the Japanese mealworm beetle is causing damage to feed in chicken coops and is a problem in many places.

[Takehiko Nakane]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

昆虫綱甲虫目ゴミムシダマシ科に属する昆虫。日本各地のほか、シベリア、ヨーロッパ、北アメリカに分布し、貯蔵穀類の害虫に数えられるが害は少ない。体長15ミリメートル内外。黒褐色で長形、多少後方が幅広い。6～7月ごろから現れ、朽ち木にみられ、また倉庫や納屋などにいる。幼虫は細い円筒形で黒褐色、成幼虫とも穀類の屑(くず)などを食べる。

　ゴミムシダマシ科darkling beetles/Tenebrionidaeは世界中に広く分布し、とくに熱帯域に多く、1万5000種以上が知られ、日本産として200種以上が記録されている。体長2～35ミリメートルぐらい。形はきわめて変化に富み、ほかの甲虫のどれにも似た形の種類があるといわれるほどである。全体的にみると黒色の種類が多いが、虹(にじ)の金属光沢をもつニジゴミムシダマシのようなものや、モンキゴミムシダマシなど赤い紋をもつものなど、いろいろある。形もテントウゴミムシダマシのように半球形のものから、卵形、楕円(だえん)板状、円筒形、ときにはヒサゴゴミムシダマシのようにひょうたん形などさまざまである。触角は先端へ徐々に幅を増し、前脚(ぜんきゃく)の基節は後方が閉じ、跗節(ふせつ)は5節で後脚だけ4節、つめは単純であるなどの特徴をもつ。

　日本には、海外の砂漠や不毛の地にいるような種類はいないが、枯れ木や朽ち木にいるキマワリ、ヒサゴゴミムシダマシ、オオゴミムシダマシ、エグリゴミムシダマシなどや、キノコに集まるクワガタゴミムシダマシ、ナガニジゴミムシダマシ、キノコゴミムシダマシ、ツノゴミムシダマシなどは多く、コケなどを食べるテントウゴミムシダマシの類もいる。また、海浜や川原に多いスナゴミムシダマシ、海岸にいるゴモクゴミムシダマシ、ホネゴミムシダマシやハマベゴミムシダマシの類もみられる。このほか貯蔵穀類につく種類は世界共通や広い分布域をもつものが多く、日本にもコメノゴミムシダマシ、コクヌストモドキなど多く、ガイマイゴミムシダマシは、鶏舎内の飼料に発生する被害が各地におこり、問題になっている。

［中根猛彦］

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