Page 248 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

BUTTERFLY CATERPILLARS

FAMILY Nymphalidae
DISTRIBUTION North America, from southern Canada to northern Mexico
HABITAT Low-elevation riparian habitats, usually along watercourses
HOST PLANTS Willow (Salix spp.), poplar (Populus spp.), plum (Prunus spp.),
and apple (Malus spp.)
NOTE Horned caterpillar that has “bird dropping” markings
CONSERVATION STATUS Not evaluated, but locally common

ADULT WINGSPAN
3–3⅛ in (75–80 mm)
CATERPILLAR LENGTH

1⅜–1½ in (35–38 mm)
LIMENITIS ARCHIPPUS
VICEROY
246
(CRAMER, 1776)

Female Viceroys lay eggs singly on the upper side tips or edges
of host plant leaves. After six days, the caterpillars hatch and
begin to feed, mostly at night. First instars feed at the tip of a
leaf, leaving the midrib exposed. On this, the caterpillar spins
a silk mat and rests there, adding frass pellets to the tip of the
midrib to extend the pier. The larvae use piers until the third
instar, likely to provide protection from predators, which may
have an aversion to frass. For defense, older instars use crypsis
and aggression—waving their spiked horns when disturbed.

The third instar overwinters in a shelter constructed from
host plant leaves. Pupation usually occurs on the host plant,
and development from egg to adults takes as little as 40 days.
The adult Viceroy is a mimic of the Monarch (Danaus plexippus),
gaining protection from the latter’s distastefulness. Recent
research indicates that, like Monarch caterpillars, Viceroy larvae
also sequester toxins from their host plants for defense.

The Viceroy caterpillar is smooth and reddish
brown with a white saddle and white posterior
ventral markings. It also displays tiny, blue
spots and long, spiked horns. The head is
orange and at with knobby protuberances. Actual size
In some populations, the ground color is
green or dark brown.