Page 313 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

MOTH CATERPILLARS

FAMILY Limacodidae
DISTRIBUTION United States, from New England south to Mississippi,
west to Missouri

HABITAT Forests, woodlands, and eld edges
HOST PLANTS Oak (Quercus spp.), beech (Fagus spp.), willow (Salix spp.),
and other deciduous trees
NOTE Slug caterpillar often mistakenly dismissed as a leaf abnormality
CONSERVATION STATUS Not evaluated

ADULT WINGSPAN
⁄ –1 ⁄ in (15–43 mm)
CATERPILLAR LENGTH
⅜ in (10 mm)
TORTRICIDIA PALLIDA
RED-CROSSED BUTTON SLUG 311

(HERRICH-SCHAFFER, 1854)

The Red-crossed Button Slug and other button slug caterpillars
appear to the naked eye as colorful oval (or round) “buttons”
on the undersides of leaves, usually near the leaf edges. Solitary
in nature, they are rarely observed occupying the same leaf
as other caterpillars. While some have been seen “rocking in

place” at three to ve-second intervals, the majority are inactive
when encountered and easily mistaken for leaf abnormalities.
Early instars typically begin to appear in early July and feed
by skeletonizing leaf surfaces. Mature caterpillars can be found
feeding along leaf edges during August and September. There
is one generation in the north of the range, two in the south.

Observation of the genus suggests that button slugs are localized
within their range, as one small section of forest can yield
multiple encounters, while trees a short distance away may be Actual size

button slug-free. Tortricidia pallida is di cult to di erentiate

from the Abbreviated Button Slug (T. exuosa), particularly

during early instars. Some experts believe that they could
be the same species.

The Red-crossed Button Slug caterpillar is
oval shaped and lime green, with a distinctive
brownish-red saddle across the dorsum.
Considerable variation in color and markings
occurs, fully manifested during later instars.
Side peripheral markings are noticeably wider
than on the Abbreviated Button Slug (Tortricidia
exuosa). Thin, yellow, and brighter red outlines
border the saddle on mature caterpillars.