Page 598 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

MOTH CATERPILLARS

FAMILY Noctuidae
DISTRIBUTION Europe, including southern and eastern Scandinavia, east across
Russia and central Asia to Magadan, Mongolia, China, and Korea
HABITAT Woodlands, scrub, and often parklands and gardens
HOST PLANTS Wide variety of broadleaved trees and bushes, including willow
(Salix spp.), lime (Tilia spp.), oak (Quercus spp.), hawthorn
(Crataegus spp.), and rose (Rosa spp.)
NOTE Hairy caterpillar that has a yellow dorsal stripe and hump
CONSERVATION STATUS Not evaluated

ADULT WINGSPAN
1 ⁄ –1¾ in (33–45 mm)
CATERPILLAR LENGTH
1 ⁄ –1 ⁄ in (36–40 mm)
ACRONICTA PSI
GREY DAGGER
596
(LINNAEUS, 1758)

The Grey Dagger caterpillar hatches from a domed, whitish
egg laid singly on a leaf. It feeds and rests openly on the food
plant, in one or two generations from June to October. When
the larva is fully fed, the yellow stripe along its back turns white
and it is then often seen descending the tree to seek out a cavity
under loose bark, rotten wood, or the ground, in which it forms
a glossy brown pupa in a tough cocoon. This stage overwinters,
with adults eclosing the following summer.

Few noctuid caterpillars are noticeably hairy, but the
Acronictinae (dagger moths, named for the forewing markings)
are an exception. The adult Grey Dagger and Dark Dagger
(Acronicta tridens) are almost identical, but the caterpillars
are easy to tell apart. The Dark Dagger has a much shorter
protuberance on the fourth segment, and the dorsal stripe is

orange-red and yellow (or white and yellow) with a ne dark
central line; it also has some white spots.

The Grey Dagger caterpillar has sparse, long hairs
on the back and shorter, denser ones on the sides.
It is gray in color, with a broad, clear, yellow stripe
on the back. Laterally, there are vertical, orange-red
Actual size
marks, blocks of irregular, black spots, and a broad,
white or sometimes yellowish stripe low down.
It has a long, eshy, blackish protuberance on the
fourth segment and a gray hump near the tail end.