「ジャノメセセリ」とは [世界の蝶 / Butterflies World]


Ocellata albata (Peru) UP.jpg
▲ジャノメセセリ Ocella albata (Peru:大木隆コレクション)

 今回は中南米のセセリチョウから一風変わったものを紹介したい。眼状紋(ocellus 複数形はoceli)とは、和名でも「蛇の目」とジャノメチョウでお馴染みの目玉模様である。大きな眼状紋は天敵を驚かすため、小さな眼状紋は天敵の攻撃をそこに集中させることで頭部や胸部など重要な体の部位を守るため、などと説明されることが多い。眼状紋はタテハチョウ科の種に幅広く見られるが、面白いことに他の科では顕著な例は余り多くない。

Ocellata albata (Peru) UP.jpg
Ocella albata (Peru; in Mr. Takashi Ohki's collection )

Once, this blog presented an article on a peculiar lycaenid from Central
and South Americas, Banded Cycadian (Theorema sapho).
Probably because the species was hardly known among Japanese butterfly
lovers, the article has become popular, enjoying many accesses.

Today, I would like to introduce an unique hesperiid from Central and
South Americas. Eyespot (ocellus in Latin singular; plural and feminine,
ocella) patterns are familiar design patterns in Japan as well as known
to be found among satyr butterflies (browns). It is often explained that
large eyespot patterns, resembling the eyes of large preditors, scare
the natural enemies whereas small eyespot patterns attract their
attention to the patterns away from the important body parts, e.g. head
and thorax, to save the species when attacked. Eyespots are widely found
on wings among the nymphalid butterflies. Interesting, however, not many
species in other families are known with eyespot patterns.

Ocella, a minor genus among the Central and South American hesperiids,
is apparently named after the eyespot pattens. According to Evans (1953),
who establilshed the genus, it is placed in subgroup Nisoniades in
group Telemiades close to tribe Tagiadini (comprising Tagiades, etc.).
Ocella albata, shown above, is the nomiotypical species of the genus,
which comprises this species and additional two. All have eyespot
patterns around the discal cell of the forewing. Their apparences may
justify us to call them “eyespot skippers”.

The present blogger is mcuh more familiar with Asian butterflies.
Although he knows many Asian skippers with transparent spots, he knows
none which has eyespot patterns. He cannot help being curious but with
no answer yet. Why have the species of this genus from the Central and
South Americas become to have such eyespot patterns?

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