Wisconsin Native Caterpillars
Spicebush Swallowtail Caterpillar
Genus-Species: Papilio trailus
Description: Young caterpillars resemble bird
droppings: chocolate brown with a white saddle mark. Older caterpillars are bright green
with 2 large black and yellow eyespots on the thorax behind the true head. Another pair
of spots occurs behind these but lacks the “eye.” A double row of small blue circles
extends down each side of the back.
Chrysalis: The chrysalis is either mottled brown
or green, depending on the time of year and the structure to which it is attached. Brown
chrysalides usually occur in the fall and overwinter.
Description: Young caterpillars resemble bird droppings:
chocolate brown with a white saddle mark. They also fold the edge of a host plant leaf over to form
a flap that provides shelter. Older caterpillars are bright green with two large black and yellow
eyespots on the thorax behind the true head. Another pair of spots occurs behind these but lacks
the “eye.” A double row of small blue circles extends down each side of the back.
Host Plants: Spicebush (Lindera benzoin), sassafras
trees (Sassafras albidum); perhaps prickly ash (Zanthoxylum americanum), tulip tree (Liriodendron
tulipifera), sweetbay (Magnolia virginiana), camphor (Cinnamomum camphora), and redbay
(Persea borbonia).
Habitat: Woodlands, and open areas near woodlands.
Comments: The Spicebush Swallowtail is an uncommon
stray into Wisconsin. The main larval food plants of this species are Sassafras and Spicebush,
neither of which is native to Wisconsin.