Yellow-dusted cream moth

Description

Yellow-dusted cream moth is a medium-sized typical geometer moth. It occurs across the United States and southern Canada. It is common in Minnesota. It is found in deciduous and mixed woodlands and in open streamside thickets. Larvae feed mostly on willow but also on birch, blueberry, poplar.

Adults have slender bodies and relatively large wings, with a wingspan of 1 1⁄16″ to 1 3⁄16″ (27 to 30 mm).

The antennae on the female are slender and thread-like. On the male the antennae are branched, feather-like, on one side (pectinate).

The wings are cream-colored. On the forewings there are faint, yellowish-brown, antemedial (AM), median, and postmedial (PM) lines. The lines are broad, slightly jagged, and mostly parallel. The median and PM lines continue on the hindwings. All of the wings are dusted with numerous yellowish-brown scales.

The caterpillar, called a spanworm, is somewhat flattened and about 1″ (2.5 cm) long. The ground color may be green, bluish-green, or yellowish-green to brown. On the first through seventh abdominal segments (A1 through A7) there is a small black spot in the middle of the leading margin (middorsal). There is often pink on both sides of each spot. There is a bold, pale, subdorsal stripe and a narrow, wavy, pale, subspiracular stripe. There are 3 pairs of legs on the thorax, one on each thoracic segment, and just 2 pairs of leg-like structures (prolegs) on the abdomen, one pair on A6 and one pair on A10. The prolegs are pinkish. The head is squarish and is projected forward. It has a reddish, dark, cheek line and reddish antennae. Mature caterpillars are active from June onward.

Size

Wingspan: 1 1⁄16″ to 1 3⁄16″ (27 to 30 mm)

Similar Species

Larva of yellow-dusted cream moth cannot be reliably distinguished from larvae of the closely related pink-striped willow spanworm except by raising them to adults. Both occur in Minnesota.

Habitat

Deciduous and mixed woodlands, open streamside thickets

Ecology

Season

Two generations per year: May through August

Behavior

Adults rest with their wings spread flat. They are active at night and will come to lights.

Life Cycle

Larva Food/Hosts

Willow, birch, blueberry, and sometimes poplar

Adult Food