triangle-backed pelochrista moth

not listed

NNR - Unranked

SNR - Unranked

not listed

Triangle-backed pelochrista moth is one of four closely related and similar moths that comprise the dorsisignatana species group or Pelochrista dorsisignatana section. Two of the four species, Pelochrista dorsisignatana and Pelochrista similiana, occur in Minnesota, They are easily distinguished by their markings.

Triangle-backed pelochrista moth is a small, late season, leafroller moth. It occurs in the United States and southern Canada east of the Great Plains, in Colorado, and in British Columbia and Alberta Canada. Caterpillars feed on the roots, lower shoots, and emerging buds of Canada goldenrod and giant goldenrod. Adults are found in open and shaded areas with their host plants. They have been observed from July through November, but their peak occurrence is in August and September.

Adults are ⅜″ (10 mm) in length and have a ½″ to ⅞″ (12 to 22 mm) wingspan. Females are slightly larger than males. Size is often given in terms of forewing length. The forewing length of females is ⅜″ to ½″ (8.8 to 11.4 mm), with a mean length of ⅜″ (9.9 mm). The forewing length of males is ¼″ to ½″ (6.6 to 11.5 mm), with a mean length of ⅜″ (9.3 mm).

The antennae are long and thread-like. They are held straight back over the body when at rest. The finger-like sensory organs (palps) attached to the mouth are long and densely hairy. They are projected forward, appearing like a fuzzy snout. The head and palps are pale gray to reddish-brown, the same as the base color of the forewings.

The forewings are narrower at the base and wider at the rear, giving the moth a tapered appearance. They are pale gray to reddish-brown and extensively overlayed with fine straight (striate) and wavy (vermiculate) lines. There are three prominent, reddish-brown to blackish-brown bands thinly outlined with white: a wide, oval band (subbasal band) extending from the forward one-third wing length to about the middle of the wing; a similarly sized, wide, oblique band (median band) extending rearward from near the leading edge (costal margin) just beyond the middle to the inner margin; and a narrow, oblique band (subterminal band) that begins at the inner (anal) angle at the end of the wing and extends inward. All of the bands are separated – the median band does not touch the subbasal band or the subterminal band. The median band fades as it approaches the costal margin and almost never reaches it. The subterminal band is much lighter and often breaks up before reaching the costal margin. There is no eyespot. The terminal band is dark with white, “salt-and-pepper” speckling.

The hindwing is light brown to brownish-gray.

Total length: ⅜″ (10 mm)

Wingspan: ½″ to ⅞″ (12 to 22 mm)

Open and shaded areas with goldenrods

August and September

Adults are active at night and will come to lights.

The wings are held tight to the body when at rest.

The female lays eggs on a host plant stem close to the ground. When the eggs hatch, the larvae bore into the stem and tunnel down to the roots, where they spend the winter.

Canada goldenrod and giant goldenrod

Sources

4, 21, 24, 29, 30, 75, 82.

Common

Genus
A recent phylogenetic analysis of the Eucosma, Pelochrista, and Phaneta genera (Gilligan et al., 2013) resulted in a complete reordering of the three genera and the creation of a new genus. Nearly all North American (Nearctic) Phaneta, approximately half of the Nearctic species previously assigned to Eucosma or Pelochrista, and all Eurasian (Palearctic) species previously assigned to Eucosma except guentheri and lugubrana, were transferred to Pelochrista.

Species
This species was formerly classified as Eucosma dorsisignatana and was known by the common name triangle-backed eucosma moth. In 2013 it was transferred to the genus Pelochrista and is now known by the name triangle-backed pelochrista moth.

Pelochrista dorsisignatana (triangle-backed pelochrista moth)

Location: Barnes Prairie, Racine Co., WI