Page 64 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

BUTTERFLY CATERPILLARS

FAMILY Papilionidae
DISTRIBUTION Northern Myanmar, northern Mongolia, Russian Far East,
China, Chinese Taipei, Korea, Japan, Ogasawara Islands,
Guam, and Hawaii
HABITAT Woods, urban and suburban areas, and orange orchards
HOST PLANTS Rutaceae, such as Phellodendron amurense, Poncirus trifoliata,
Zanthoxylum spp., and cultivated Citrus spp.
NOTE Caterpillar that was once worshipped as a god in Japan
CONSERVATION STATUS Not evaluated, but common

ADULT WINGSPAN
1¾–4 in (45–100 mm)
CATERPILLAR LENGTH
2–2⅜ in (50–60 mm)
PAPILIO XUTHUS
ASIAN SWALLOWTAIL
62
LINNAEUS, 1767

Like many Papilio species, the Asian Swallowtail caterpillar
starts out looking like a bird dropping and ends up resembling
a snake. The larvae feed initially on the upper surface of the
leaf (where bird droppings land), but in a change regulated by
juvenile hormones (JHs) they become green and snakelike,
sometimes rearing up with a swelling thorax. The larvae can
defoliate Citrus trees. Those developing later in the year may
overwinter as pupae, but consequent adults eclosing in the spring
tend to be much smaller than the summer generations.

The Asian Swallowtail is among the best-studied butterfl ies,
especially in Japan, where researchers have conducted many
The Asian Swallowtail caterpillar is green experiments on learning and color preferences in Papilio
with eyespots on the second thoracic segment, xuthus adults and, more recently, larvae. The latest research
a broad, dark dorsal band separating thorax and
abdomen, and several transverse bands that are on the genetics of color patterning found that seven genes are
darker green, and sometimes green and white.

There is also a longitudinal white stripe with involved in regulating color changes between different larval
a thick, black border running along the prolegs. stages. The species was an ancient celebrity, too; according to the
The head is green and, when disturbed, long,
yellow, paired osmeteria are everted behind it. eighth-century Nihon Shoki (“Chronicles of Japan”), a green,
Citrus-eating caterpillar, now identified as P. xuthus, was once

worshipped as a God of the Everlasting World.

Actual size