Page 494 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

MOTH CATERPILLARS

FAMILY Geometridae
DISTRIBUTION From southern Canada south to Georgia (and possibly to the
Florida panhandle) in the eastern United States and to northern
California in the west
HABITAT Deciduous and mixed forests
HOST PLANTS Alder (Alnus spp.), ash (Fraxinus spp.), birch (Betula spp.),
acer (Acer spp.), oak (Quercus spp.), and poplar (Populus spp.)
NOTE Sticklike caterpillar that blends in with its host plant twigs
CONSERVATION STATUS Not evaluated, but common

ADULT WINGSPAN
1 ⁄ –2⅜ in (43–60 mm)
CATERPILLAR LENGTH
2¾–3⅛ in (70–80 mm)
ENNOMOS MAGNARIA
MAPLE SPANWORM
492
GUENÉE, [1858]

Maple Spanworm caterpillars hatch from overwintering eggs
laid in rows on their host plant and can be found between May
and August. Both edible and abundant, the larvae have evolved a
remarkable ability to camou age themselves. So as not to create

a searchable pattern for predators, the green, brown, or gray
coloring of their body varies, and they also blend perfectly with
their host plant by assuming a sti , twiglike position during the

day. At maturity, the larvae pupate in a cocoon woven between
the leaves of the host plant.

Although listed as feeding on apples, the caterpillars apparently
inflict no economic damage. However, like many other
inchworms, they have an important ecological signi cance as

food for numerous bird species as well as other insects, such
as predatory wasps. The adults y in a single generation from

July to October (depending on the latitude), and, just like the
larvae, the moths are masters of camou age, matching fallen

leaves perfectly both in shape and color.

Actual size

The Maple Spanworm caterpillar is a twig
mimic with a green, brown, or gray body and
tiny, white spotting that simulates the spotting
on the bark of the host plant trees. Skin folds
and swellings on two or three of the abdominal
segments resemble leaf scars. The head is green,
attened, and pointed forward, with a pair of
prominent reddish antennae. The metathoracic
legs are swollen at their base, resembling
another leaf scar.