Tsubameshijimi (English name) short-tailed blue

A butterfly belonging to the family Lycaenidae in the order Lepidoptera of the class Insecta. It is widely distributed in the Eurasian continent, and is commonly found throughout Japan, but is not native to the Nansei Islands south of the Tokara Islands. Its Japanese name was given because the tail-like protrusions on its hindwings resemble a swallow's tail. Its wingspan is about 25 mm. It reproduces several times from early spring to autumn and is polyvoltine. It can be found in grasslands such as roadsides, grasslands, riverbanks, banks and farmland, and flies low to be easily collected, sucking nectar from various flowers. The larvae feed on the shoots, flower buds and fruits of the Fabaceae family, such as Japanese bush clover and other bush clover, Japanese wisteria, pea, white clover and Japanese knotweed.

A species closely related to this species is the Taiwan swallowtail butterfly E. lactturnus , which is found in Shikoku, Kyushu (including Tanegashima and Yakushima), and Okinawa Island. In Honshu, its habitat is only known to be in Wakayama Prefecture. In all of these habitats, occurrence is localized. The food plant for the larvae is the grass sedge of the legume family.

[Takashi Shiramizu]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

昆虫綱鱗翅(りんし)目シジミチョウ科に属するチョウ。ユーラシア大陸に広く分布する種で、日本でも全国各地に普通、吐噶喇(とから)列島以南の南西諸島には土着しない。和名は、後ろばねの尾状突起をツバメの尾に見立てて名づけられた。はねの開張25ミリメートル内外。早春より秋まで数回の発生を繰り返し、多化性。路傍、草原、河岸、堤、畑地などの草地にみられ、低く飛び採集は容易、各種の草花で吸蜜(みつ)する。幼虫の食草はメドハギその他のハギ類、クサフジ、エンドウ、シロツメクサ、コマツナギなどのマメ科で、新芽、花蕾(からい)、実などを食べる。

　本種に近似のものにタイワンツバメシジミE. lacturnusがあり、これは四国、九州（種子島(たねがしま)、屋久島(やくしま)を含む）、沖縄本島に産する。本州では和歌山県下にその生息地が知られるのみ。いずれの産地でも発生地は局部的である。幼虫の食草はマメ科のシバハギ。

［白水　隆］

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