Page 62 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

BUTTERFLY CATERPILLARS

FAMILY Papilionidae
DISTRIBUTION United States, from New England to Florida, west to Texas
and Colorado
HABITAT Marshlands, parks, gardens, meadows, and woodland edges
HOST PLANTS Spicebush (Lindera benzoin) and Sassafras (Sassafras albidum)
NOTE Caterpillar that is a structure-building master of mimicry
CONSERVATION STATUS Not evaluated, but may be rare in periphery of its range

ADULT WINGSPAN
3–4 in (76–100 mm)
CATERPILLAR LENGTH
2⅛ in (55 mm)
PAPILIO TROILUS
SPICEBUSH SWALLOWTAIL
60
LINNAEUS, 1758

Spicebush Swallowtail caterpillars spend their complete larval
cycle within the leaves of the tree upon which the eggs were
originally deposited. Young larvae are bird-dropping mimics
that vary in coloration from green to brown, occasionally
with white saddles across abdominal segments three and eight.
When the caterpillar is inactive, a leaf enclosure protects it
from predation. By the fourth instar, the body color changes
to lime green, transforming the caterpillar into nature’s most
convincing snake look-alike. Large eyespots and a retractable
“forked tongue” (osmeterium) complete the illusion.

The larva pupates within a silken harness, which hangs from
the underside of a low-lying leaf of the host tree. The pupa can
be green or brown, depending on the seasonal coloration of the

surrounding foliage. The adult Spicebush Swallowtail butterfly
also employs mimicry to avoid predation by closely imitating
the Pipevine Swallowtail (Battus philenor), a similarly patterned

but foul-tasting butterfly, which shares its range.

The Spicebush Swallowtail caterpillar’s most
recognizable late-instar form is lime green above,
tan below, with a yellow stripe separating the
colors. Four orange eyespots are present on
the upper thorax. The front two thoracic spots
Actual size are large and contain black “pupils” with white
highlights. A series of smaller blue spots extend
vertically along the abdomen.