salt marsh moth

not listed

N5 - Secure

not listed

Salt marsh moth is a common and widespread tiger moth. It occurs throughout the United States and southern Canada, and south into Central America. It is common in Minnesota.

Adults are found in open areas, including open woodlands, prairies, meadows, agricultural fields, abandoned fields, and all kinds of marshes, including salt marshes. They are active from May to September in Minnesota. The larvae feed mostly on a wide variety of herbaceous plants, but also on the leaves of trees and shrubs. They are agricultural pests of many crops, including cabbage, cotton, walnuts, apple trees, tobacco, pea, potato, clovers, and maize.

Adults are 1⅛″ (29 mm) in length and have a 1¾″ to 2⅝″ (45 to 68 mm) wingspan.

The forewings are white above with five large black spots well-spaced along the leading edge (costal margin). There are also a few to many small, irregular, black spots along what would be the antemedial (AM), median, postmedial (PM), subterminal (ST), and terminal lines. On males, the underside of the forewing is sometimes tinted yellow or orangish-yellow, and the fringe is sometimes that color. On females the underside is white, sometimes with pale yellow tinting along the costal margin and the main veins. The fringe is always white.

On males, the hindwings are dark yellow or yellowish-orange. On females, the hindwings are white. On both sexes, there are three or four black spots on the hindwing.

On males, the underside of the thorax is orange. On females it is white.

The abdomen is mostly orange above and below, white on the sides. The tip of the abdomen is white. On most abdominal segments there is a black spot above in the middle (middorsal), two black spots on each side, and a black spot on the underside. Males have a pair of internal, glandular structures (coremata) that can be extended (everted) and inflated. Each corema bears a hair pencil with pheromones the male uses to court a female.

The third segment (femur) of each leg is mostly yellowish-orange, black just at the base. The end part of the leg (tarsus) is black with white stripes.

The caterpillar is up to 23⁄16″ in length and is extremely variable in appearance. Mature caterpillars are usually dark, often black and mottled or striped with yellow. Sometimes they are yellowish or straw-colored. The breathing pores (spiracles) are white. Each thoracic and abdominal segment has six orange or black warts that bear a dense tuft of long, erect hairs (setae). The setae are mostly soft, not stiff or bristly. They may be cream-colored or grayish to yellowish or dark brown. At the end of the abdomen the setae are especially long.

Total length: 1⅛″ (29 mm)

Wingspan: 1¾″ to 2⅝″ (45 to 68 mm)

Open woodlands, prairies, meadows, agricultural fields, abandoned fields, and marshes

Two generations per year in Minnesota: May to September

Adults are active at night and will come to lights.

Larvae are fast movers and active dispersers. They are commonly seen moving along the ground in large numbers in search of food plants.

Pupae overwinter in a cocoon, and adults emerge in early spring. Adults are short-lived. Females mate, lay eggs, and die within five days after emerging.

A wide variety of herbaceous plants, trees, and shrubs

Sources

4, 21, 24, 27, 29, 30, 71, 75, 82, 83.

Common and widespread

Until recently, tiger moths and lichen moths were treated as a separate family Arctiidae. A recently published monograph (Lafontaine and Schmidt, 2010) contended that the Arctiidae “were more closely related to groups within the Noctuidae than to non-noctuid families.” The Arctiidae were transferred intact to the family Erebidae as a subfamily (Arctiinae). The former subfamilies are now tribes and the former tribes are now subtribes.

Location: a prairie in Norman Co. Mn.