Page 27 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

CATERPILLAR DEFENSES

leaf-eating caterpillars are green, blending into the foliage, while those that

feed on flowers may match the red, yellow, or white markings of their
flower food, or the colors of other plant parts. Grass-feeding caterpillars
are often green with paler stripes, while a number of Geometridae moth
caterpillars are convincingly twiglike in appearance. The Camouflaged

Looper moth caterpillar (Synchlora aerata) takes disguise a step further,
adorning its body with petals and other plant fragments.
Some species have bolder markings, often white or
yellow, that break up the background color, blurring
their outline. Posture can also change a caterpillar’s

appearance. For instance, mid-instar caterpillars of the
California Sister (Adelpha californica) rest in a Loch
Ness Monster-type posture, making them disappear
against the lobed oak leaves of their host tree. Others

mimic bird droppings, such as the early instars of many
swallowtail species of the Papilionidae family, which
are black or dark brown with a white “saddle.”

FRASS DEFENSES
Reducing telltale odors is a further protective measure.

Most invertebrate enemies of caterpillars find their prey
by scent. One likely significant source is caterpillar
feces, called frass. Some skipper and pierid caterpillars use their anal comb above The Pagoda
Bagworm Moth
to fling frass for distances of up to 40 times their own body length. Caterpillar (Pagodiella
hekmeyri), like other
Rather than disposing of frass, however, some caterpillars, including bagworms, spends
its larval life inside
web-building species, substantially contaminate their nests with it. As a a mobile home of
silk, leaf, and other
result, the frass odor of these species may somehow be neutralized or fragments, adding
extensions as it grows.
disguised. Early instars of the California Sister eat around the midrib of a The shelter, built from
available construction
leaf, then use frass pellets silked together to extend this midrib “pier.” materials within the
species’ habitat,
Species such as the Zebra Mosaic (Colobura dirce) and Staff Sergeant and extended as the
caterpillar develops,
(Athyma selenophora) create frass chains and barriers that appear to deter effectively conceals
it from predators.
intruders such as ants.

THREATS, SCARE TACTICS, AND CHEMICAL DETERRENTS
When concealment fails, some caterpillars display sudden movements to
try to scare an attacker, such as head-jerking and thrashing the anterior
part of the body from side to side. This tactic is most effective when
performed in unison by a large group of spiny caterpillars, such as