Species Estigmene acrea - Salt Marsh Moth - Hodges#8131

8131

Salt Marsh Caterpillar (larva), Salt Marsh Caterpillar Moth (adult), Salt Marsh Tiger (adult)

Estigmène dimorphe - En français… Ilze V-G.

Chenille des marais salants - En français… Ilze V-G.

Estigmene acrea (Drury)

Orig. Comb: Phalaena acrea Drury, 1773

* phylogenetic sequence #930317

2 spp. n. of Mex. (2nd sp. restricted to AZ)

wingspan 45-68 mm

larvae length to 55 mm

Adult: forewing white with about 20 small black spots scattered across the disk, and 5 larger black spots spaced along the costa. Males have dark yellow hindwings, those of females are mostly white (with 3 or 4 black blotches in both sexes).

Larva (caterpillar): highly variable, blond to brown to black, with long bristly hairs standing upright in dense tufts from orange or black tubercles; hairs longer at both ends of body, especially toward the rear end. Spiracles white. Moves very rapidly.

Face mainly black with yellow down the center.

Ova (egg): spherical and yellow (1)

all of North America except Alaska and Yukon - Map (MPG)

open wooded areas, meadows, farm fields, weedy waste places, prairie grasslands, and marshes - including salt marshes; adults are nocturnal and come to light

Adults fly from May to September. Adults fly year round in Texas

Larvae feed on a wide variety of mainly weedy plants including anglepod (Gonolobus), dog fennel (Eupatorium capillifolium), ground cherry (Physalis), mallow (Anoda), milkweed (Asclepias), pigweed (Amaranthus), and sicklepod (Cassia tora), plus crops such as alfalfa, asparagus, bean, beet, cabbage, carrot, celery, clover, corn, cotton, lettuce, onion, pea, potato, soybean, sugarbeet, tobacco, tomato, and turnip. On rare occasions, they also feed on leaves of deciduous trees and shrubs: alder, apple, cherry, elderberry, pear, poplar, and serviceberry, according to Handfield.

Sequester pyrrolizidine alkaloids (PA) from their food plant. The caterpillars have specialized chemoreceptors that detect PA and stimulate feeding.(2)

One generation per year in the far north, 2 in southern Quebec and Ontario, 3 or 4 generations in the south. Overwinters as a pupa in a spacious cocoon; adults emerge in early spring. Females lay 400-1200 eggs in clusters on leaves of host; eggs hatch in 4-5 days, and larvae pass through 5 instars over a period of 20-45 days; larvae are active dispersers, and are often found wandering over the soil in search of suitable food.

Life cycle images:

1. eggs. 2. early instar caterpillar on Cup Plant. 3 to 6. caterpillars, different instars and colors. 7. cocoon. 8. pupa. 9 and 10. adults

When disturbed the adults often drop to the ground, raise their wings, and emit an acrid odor from the prothoracic glands. Males (yellow hindwing) have inflatable appendages called coremata that will extend from the abdomen when gently squeezed.

See Here: ♂

In Arizona, the most common fly parasites of eggs and larva are E. mella, Gymnocarcelia ricinorum and Lespesia archippivora

Estigmene albida which has smaller and fewer black spots on the wings, and a more southern distribution (e.g. doesn't occur in Canada) - see pinned adult image by Bruce Walsh from Arizona.

Larvae of Virginian Tiger Moth are somewhat similar in some color forms, but seem to lack black facial markings, at least in BugGuide examples.

Covell, adult, p. 66, plate 13 #13,16) (3)

Wright, caterpillar and adult, pp. 98-99 (4)

Himmelman, caterpillar, plate A-2 (5)

Wagner, caterpillar, p. 464 (6)

Handfield, adult males, plate 60 #8131-1,2,3; adult female, plate 61 #8131-4; text, pp. 291-292 (7)

Powell, J. A. & P. A. Opler, Moths of Western North America, Pl. 47.19m, 47.22f; p. 269(8)

Moth Photographers Group - MPG

Featured Creatures - John Capinera, U. of Florida