Page 212 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

BUTTERFLY CATERPILLARS

FAMILY Nymphalidae
DISTRIBUTION North America, from southwest and south central Canada south
to Nebraska and New Mexico
HABITAT Sage deserts, savannahs, washes, gulches, and canyons

HOST PLANTS Rabbitbrush (Chrysothamnus viscidi orus) and eabane
(Erigeron spp.)
NOTE Spiny caterpillars that overwinter en masse underneath host plants
CONSERVATION STATUS Not evaluated, but common

ADULT WINGSPAN

1⅜–1¾ in (35–45 mm)
CATERPILLAR LENGTH
1–1 ⁄ in (25–30 mm)
CHLOSYNE ACASTUS
SAGEBRUSH CHECKERSPOT
210
(W. H. EDWARDS, 1874)

Female Sagebrush Checkerspots lay eggs in May in large
clusters of 100 to 150 on the undersides of leaves at the base of
Rabbitbrush plants. The young caterpillars hatch after six days
and feed immediately, developing until the third instar, when
they become dormant. The gregarious larvae seek refuge en
masse at the base of the plant, where they oversummer and
overwinter in dormancy. Feeding resumes in early spring,
resulting in adults during April. Post-dormancy caterpillars are
solitary, feed diurnally, and rest openly. Protection is based on
gregariousness and sheltering in the early instars, whereas later
instars depend on their spines and a ventral “neck” gland, which
The Sagebrush Checkerspot caterpillar is emits chemicals that appear to deter predators.
black with numerous tiny, white spots, and
each spiracle is encircled with a thin, white
ring. Most segments bear lateral and dorsal, Sagebrush Checkerspot butterflies can be common or even
bright yellow-orange, elongate spots that fade
with maturity. Setaceous black spines occur abundant in some areas. At such locations, caterpillars can be
in clumps on each segment. The head is black found in early spring in large numbers sunning themselves
and setaceous, increasingly so with maturity.
on bare branches of Rabbitbrush. Both host plants have
numerous narrow leaves, making it di cult to recognize larval

feeding damage.

Actual size