Page 201 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

BUTTERFLY CATERPILLARS

FAMILY Nymphalidae
DISTRIBUTION Throughout much of northern North America, Asia, and Europe
HABITAT Bogs, fens, and riparian habitats at mid-elevations
HOST PLANTS Violet (Viola spp.)
NOTE Spiny, cryptically colored, nocturnal caterpillar that is associated
with violets
CONSERVATION STATUS Not evaluated, but threatened in some locations due to
declining habitat

ADULT WINGSPAN
1¾–2 in (45–50 mm)
CATERPILLAR LENGTH
BOLORIA SELENE 1–1 ⁄ in (25–30 mm)
SILVER-BORDERED
FRITILLARY 199

(DENIS & SCHIFFERMÜLLER, 1775)

Silver-bordered Fritillary caterpillars hatch within five to
six days from eggs laid on violets. In late summer, the larvae
enter dormancy and overwinter as second to fourth instars.
Early instars feed on the undersides of violet leaves, while later
instars eat large holes from the leaf edge inward. Their survival Actual size
is based on three means of protection—concealment, spines, and
a ventral gland that produces a musky odor to deter predators.

There are ve instars, and no nests are made. Development from
rst instar to pupation takes about 30 days, with adults emerging

after a further 10 to 14 days.

There are one to three generations per season, depending on
location. Adult males patrol conspicuously over grassy, boggy
areas near violets, looking for females. After mating, females
remain concealed in the vegetation. Grazing by deer or livestock
is necessary to keep bog violets alive and healthy for Boloria The Silver-bordered Fritillary caterpillar is
selene. Without grazing, vegetative succession invariably causes purplish gray, mottled with numerous black
splotches and soft, yellow spines bearing many
extinction of both violets and Silver-bordered Fritillaries. setae. The anterior three segments are black,
and the horns on the rst segment are long and
black with yellow bases. The head is shiny black
with dark setae.