Page 17 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

FROM EGGS TO PUPATION

resembling plant parts, fungi, detritus,

or even bird droppings, caterpillar eggs
are rarely found by casual observers.
The eggs usually develop rapidly,
hatching within two to ten days, de-

pending on temperature. Sometimes,
though, they are programmed to delay
hatching, spending adverse weather
conditions—extreme cold or heat—in
a state of developmental arrest, known

as diapause. They then hatch only when
the host plants they feed on reappear. 15

LARVAL STAGES

The caterpillar hatches by cutting a
hole in the shell with its mandibles and,
according to species, may consume the
entire eggshell on the way out or leave
the empty eggshell with a telltale exit
hole. The new larva immediately sets

about feeding and protecting itself. It may move to a safer location on the ABOVE Successive
instars can differ
plant, cover itself with a silk-tied leaf shelter, or, in the case of gregarious considerably in
appearance as well
larvae, join with its siblings in creating an extensive silk-web nest. as size. This saturniid
moth caterpillar,
Caterpillars at the newly hatched stage, known as the first instar, usually Arsenura batesii, has
molted and left its
feed rapidly, often doubling in size within a few days. Once the larval spectacular, tentacled
fourth instar skin
“skin,” or integument, tightens and appears stretched, with a swelling at behind, becoming
cryptic and sticklike
the head caused by the larger, inelastic head capsule of the next instar, the in its fifth, final instar.
larva is nearing its first molt, or ecdysis. Before molting, larvae find a site
hidden from predators, spin a small pad of silk to which they attach their

claspers, and remain motionless for 12 to 48 hours.
Molting, which takes only minutes, begins at the head end, with the
integument splitting and slipping backward along the body as the larva
moves slightly forward. In most species, the next instar consumes the

old integument and soon resumes feeding. Newly molted larvae often
show temporary paler coloration, which disappears within 2 to 12 hours.
Some species have four or six instars, but most have five, molting four
times. However, where larval development is interrupted multiple times
by diapause, seven to nine instars can occur.