Spiny spider - Togegumo

This spider belongs to the Arthropoda phylum, Arachnidae family, Araneidae family. It is widely distributed in tropical regions, but in Japan it can be found as far north as Aomori Prefecture. It is often found among trees in scrub forests from the foothills to the mountainside, and spins a typical circular web. Females are 7 to 8 millimeters long, with a wide abdomen with two pairs of thick, hard, cone-shaped black protrusions on the sides and one pair on the back. The cephalothorax is black, and the abdomen is white with black spots. Males are small and have a round abdomen, and do not have the lateral protrusions like the female, only a pair on the back. A similar species, G. mammosa , is found in tropical regions south of Amami Oshima, and is named after the breast-like protrusions on its abdomen. There is a large variation in color between individuals.

[Takeo Yaginuma]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

節足動物門クモ形綱真正クモ目コガネグモ科に属するクモ。熱帯地方に広く分布するが、日本ではかなり北上して青森県までみられる。山麓(さんろく)から山腹にかけての雑木林などの樹間に多く、典型的な円網を張る。雌は体長7、8ミリメートルで、幅の広い腹部に、太くて硬い円錐(えんすい)状の黒い突起が側方に2対、後方に1対出ている。頭胸部は黒色、腹部は白色の地に黒斑(こくはん)がある。雄は小さく腹部は丸く、雌のような側方の突起はなく後方に1対あるのみ。奄美(あまみ)大島以南、熱帯地方にかけてトゲグモに似たチブサトゲグモG. mammosaがおり、腹部の突起が乳房状なのでこの名がついた。個体による色彩の変異が多い。

［八木沼健夫］

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