Large Tree Nymph (Idea leuconoe) – Wildlife of Japan

Introduction

One of the largest butterflies in Japan, the Large Tree Nymph drifts through the warm forests of the Ryukyu Islands with its slow, floating flight. It is especially common in Okinawa and Amami, and it represents the gentle atmosphere of the subtropics.

Appearance

The wingspan reaches about 12–14 cm.
Its wings show pale white surfaces with bold black veins and spots.
In addition, the butterfly glides slowly and smoothly, which makes it easy to identify.
The species is also famous for its metallic golden chrysalis.

Habitat & Distribution

In Japan, you can find the Large Tree Nymph naturally in the Amami and Okinawa Islands.
It prefers evergreen forests, forest edges, and places where its host vines grow.
Moreover, adults often appear along sunny forest margins and roadsides.

Behavior

The butterfly moves with gentle, floating wingbeats.
Adults visit flowers for nectar, and you can often watch them flying at eye level, making observation simple.

Diet

Larvae feed on Parsonsia alboflavescens, a native vine from the dogbane family.
This plant contains defensive chemicals, and as a result, the caterpillars absorb them for protection.
Adults drink nectar from various flowers.

Reproduction

In the subtropical climate of the Ryukyus, adults appear during much of the year.
Females lay eggs on their host vines, and after several larval stages, the golden chrysalis forms.

Conservation

The species lives widely across Southeast Asia, so it is not considered globally threatened.
However, in Japan, its stable populations depend on preserving lowland forests and native host vines.

Author’s Impression

I encountered the Large Tree Nymph on Ishigaki Island. Seeing such a large butterfly glide so elegantly was truly breathtaking. Its gentle, floating flight perfectly captures the atmosphere of the southern islands.