Page 549 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

MOTH CATERPILLARS

FAMILY Erebidae
DISTRIBUTION
DISTRIBUTION
DIS TRIBUTION United States and southern Canada
HABITAT T Oak forests and suburbs where oaks are present
HABIT
HABITAT
A
HOST PLANTS
HOST PLANTS
HOS T PLANT S Oak (Quercus spp.), including black, red, and white oaks
NOTE
NOTE
NO TE Cryptic caterpillar that blends with lichens on tree bark
CONSERV A TION S T A TUS Not evaluated, but common
CONSERVATION STATUS
CONSERVATION STATUS
ADULT WINGSPAN
2 ⁄ –3¼ in (65–82 mm)
CATERPILLAR LENGTH
2⅜–2¾ in (60–70 mm)
CATOCALA ILIA
ILIA UNDERWING 547

CRAMER, 1780

Ilia Underwing caterpillars hatch in the spring from eggs
that have overwintered. The species is most common in
eastern North America, where studies suggest that the larvae
prefer to feed on the Bear or Scrub Oak (Quercus ilicifolia).
In Connecticut, they hatch in the last few days of April and feed
on fresh growth, which is the only food suitable for the young
caterpillars. Catocala larvae are all cryptic, their colors blending
with the bark on which they rest, although C. ilia occasionally

mimics brighter lichens. Their camou age defense and diet of
large, nontoxic trees indicate that the larvae are palatable to birds
and other predators. Following pupation, adults eclose and y

from June to September.

Worldwide there are more than 150 di erent Catocala species,
providing a uniform group collectively referred to as
“underwings” for their mostly bright-colored hindwings, which
are hidden at rest beneath cryptic forewings. In the western
United States, the subspecies C. ilia zoe is quite distinctive and
possibly represents a different species from the eastern
populations. Catocala ilia is most easily confused with C.
aholibah, another oak-feeding species.

The Ilia Underwing caterpillar is mottled green
and black or gray and black with small dorsal
bumps, resulting in a cryptic color pattern that
matches the lichens on oak branches. The larva
is attened ventrally, with fringes of hairs that
enhance its camou age against the substrate.
When the larva is ipped over, its strikingly
di erent ventral surface can be seen—pink
purple in color with a wide, black, transverse
stripe on each segment.
Actual size