Black swallowtail（クロアゲハ）

by M. Iwabuchi

Introduction

Black swallowtail is the most beautiful black butterfly. It is the largest of the swallowtails. It resembles other kinds when it is larva or a pupa, but it differs greatly when it becomes an imago. It is seen most ordinarily in black butterfly. So some people observe.

Taxonomy

Black swallowtail is a scientific name Papilio protenor. It is a kind of the butterfly classified into butterfly order and the family of a swallowtail.

Range

It is widely distributed from Taiwan and China to Himalaya. In Japan, it is distributed over Honshu (Akita and south of Iwate), Shikoku, Kyushu and Amami Oshima. There isn’t in Hokkaido. And it is few in the lowlands of the Tohoku Region. It is found in shaded places, such as a place where trees grew thick. But it seen from town to mountain. On a mountain path, it often sees taking on water from the damp ground.

Ecology

Black swallowtail’s color is blackish. The length of the front wing of the imago is about 45-70 mm. Red points are located on an edge of the back side of a hind wing. Black swallowtail of Japan is a caudate process to a wing. Male’s front edge of  the hind wing has a white band. Growing white band changes yellowish. Female’s red points are more beautiful than male’s one.

It opens a wing when it stops between trees. But it closes a wing when it sleeps. This is common behavior in swallowtails.

It generates 2 to 4 times in September from April. There are two types of spring type and summer type. Spring type is smaller, progress red points and deeper-colored black than summer type.

It oviposits usually on the branch or the trunk of  a tree. The egg becomes orange color from yellow.　Finally the egg becomes light brown. It hatches in about one week.

The larva becomes green from brownish. The green larva resembles swallowtail’s larva. But the brownish larva is different. The color is glossy and the pattern is like the dropping of a bird. Green larva takes off thing like the red horn which gives off a smell if it feels danger. The larva eats the leaf of citrus fruits, such as a trifoliate, a yuzu, a prickly ash and skimmia.

The chrysalis is two patterns with brown or green. The brown chrysalis stays over the winter. The chrysalis becomes black toward hatching. And it breaks a chrysalis and comes out.　The flow of these series is observable also in the garden.

Where to see in Kochi

In Kochi, black swallowtail is seen at a roadside in October from May because Kochi is warm. Kochi is the place of production of yuzu. So you will see black swallowtail’s egg or larva or chrysalis if you turn the leaf of a yuzu. It is a familiar butterfly.