Estigmene

Hübner, 1820

Ermine Moths

Estigmene is a of in the Erebidae, erected by Jacob in 1820. in this genus are to North and Central America. The genus has undergone taxonomic revision, with many African and Asian species formerly included now separated into different genera. The most well-known species is Estigmene acrea, commonly called the saltmarsh or woollybear, which is a widespread and occasional agricultural pest.

Estigmene acrea by (c) Jake McCumber, some rights reserved (CC BY), uploaded by Jake McCumber. Used under a CC-BY license.

Estigmene acrea by (c) Jon Sullivan, some rights reserved (CC BY). Used under a CC-BY license.

Estigmene acrea by (c) Justin Williams, some rights reserved (CC BY), uploaded by Justin Williams. Used under a CC-BY license.

Pronunciation

How to pronounce Estigmene: /ɛˈstɪɡməˌni/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Members of Estigmene can be distinguished from related by characteristics and patterns. typically have or pale with dark spotting or patterning. are densely hairy ('woolly'), with variable coloration ranging from to orange to black depending on and . E. acrea larvae are distinguished from the banded (Pyrrharctia isabella) by their lack of distinct black and more uniform orange or yellow coloration.

Images

Habitat

Open fields, meadows, agricultural areas, and disturbed where plants grow. are commonly found on low-growing .

Distribution

North and Central America. The is to this region, with E. acrea specifically recorded throughout the United States, extending to Central America and southern Canada (Ontario and Quebec).

Seasonality

are active during warmer months. In temperate regions, are most commonly observed in late summer and autumn, often seen dashing across roads and paths seeking sites. E. acrea appears to be (one per year) in northern parts of its range, with adults emerging in August.

Diet

are feeding on a broad range of woody and herbaceous plants. E. acrea has been documented feeding on dandelion (Taraxacum), plantain, violets, cherry, honeysuckle, and various agricultural including corn, sugarbeet, and field beans.

Life Cycle

with , , , and stages. E. acrea eggs hatch in approximately 6 days. Larvae feed through spring, summer, and autumn, as partially grown . In spring, they resume feeding briefly before pupating. The from egg to adult takes about 6 weeks under favorable conditions. Adults emerge in mid to late summer.

Behavior

are and often seen actively moving across open ground in autumn seeking sheltered sites beneath logs, stones, or leaf litter. females exhibit calling ( release) during the scotophase (dark period), with peak calling activity between 4-6 hours and again at 10 hours after dark onset. Males form where they display inflated abdominal to attract females. Mated females produce significantly less pheromone than virgin females. Larvae show food-aversion learning capabilities, avoiding plants that have previously caused illness.

Ecological Role

serve as for various and . E. acrea is a known for the ichneumon Therion morio, a parasitoid that lays in . The functions as a in early successional and agricultural .

Human Relevance

E. acrea is occasionally a pest of agricultural including corn, sugarbeet, and field beans, particularly in the southern United States. The saltmarsh is also known for its winter weather folklore, though unlike the banded , it lacks predictive banding patterns. The has been widely used in entomological research on , biology, and - interactions.

Similar Taxa

Pyrrharctia isabellaBoth are with dense hair covering; P. isabella has distinct black at and tail with orange band in middle, while Estigmene acrea lacks this banded pattern and is more uniformly colored.
Hypercompe scriboniaBoth are large, hairy ; H. scribonia is entirely black with crimson rings between body when disturbed, while E. acrea is typically orange or without black .
Spilosoma virginicaBoth are with hairy ; S. virginica larvae are with black stripes and longer, softer hair compared to the denser, shorter hair of E. acrea.

Misconceptions

The saltmarsh (E. acrea) is sometimes mistaken for the banded (Pyrrharctia isabella) in winter weather folklore. Unlike the banded woolly bear, whose orange width is claimed to predict winter severity, the uniformly orange or saltmarsh caterpillar has no such predictive value. The 'saltmarsh caterpillar' is somewhat misleading as the is not restricted to salt marsh but occurs broadly in fields, meadows, and agricultural areas.