Catocala amestris

Strecker, 1874

Three-staff Underwing

Catocala amestris, the three-staff underwing, is a North American in the Erebidae. It is listed as endangered and receives legal protection in Michigan. The has a wingspan of 4-4.5 cm and exhibits the characteristic underwing pattern of cryptic forewings concealing brightly colored hindwings. It has been documented as a new record for southern Colorado when attracted to stations, indicating potential range expansion or underreporting.

CATALOGUE-BM-PLATE CXCIX by Sir GEORGE F. HAMPSON, Bart.. Used under a Public domain license.

Catocala amestris 78481120 by Amy Chamberlin. Used under a CC BY 4.0 license.

Catocala amestris MGCL 1040559 V by Florida Museum of Natural History, McGuire Center. Used under a CC0 license.

Pronunciation

How to pronounce Catocala amestris: /ˈkætəkələ əˈmɛstrɪs/

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Identification

Distinguished from other Catocala by the specific pattern of two wavy black lines on the yellow-orange hindwing, combined with the kidney-shaped forewing blotch. The caterpillar's bluish-white ground color with yellowish dorsum, orange band, and seven thin black lateral lines provides additional identification characters. Similar underwing species may share general color patterns but differ in specific line arrangements and forewing markings.

Images

Appearance

Forewings brownish-gray with a distinct kidney-shaped blotch and mixed wavy lines beyond. Hindwings yellow-orange with two wavy black lines separating the coloration. Wingspan 1.6-1.8 inches (4-4.5 cm). Caterpillar bluish-white with yellowish coloring, an orange band, and seven thin black lateral lines.

Habitat

Dry-mesic prairies and oak forests. Dependent on presence of plants in Amorpha, which restricts its distribution even within suitable types.

Distribution

North America. Documented in Michigan (where legally protected), with records from southern Colorado indicating broader distribution than previously recognized. GBIF records confirm presence in North America.

Seasonality

active June through August. One per year.

Diet

Larval plants restricted to Amorpha ( Fabaceae). feeding habits not documented.

Host Associations

Amorpha - larval Only documented ; specificity likely contributes to rarity

Life Cycle

Complete with , larval, pupal, and stages. Caterpillar described as bluish-white with distinctive color pattern. Single with adult June-August.

Behavior

attracted to fermented (sugaring) in addition to light sources. Typically remains on periphery of lighted areas when at lights. Has been observed flying erratically before settling at light stations. Hindwing flash display used as startle defense when disturbed.

Ecological Role

Herbivore in larval stage, potentially serving as prey for . Specific ecological interactions poorly documented due to rarity.

Human Relevance

Subject of conservation concern; legally protected in Michigan. Attracted to stations during observation events, contributing to citizen science records. New state records (e.g., Colorado) demonstrate value of targeted survey efforts for rare .

Similar Taxa

Catocala aholibahSimilar large underwing with bright hindwings, but differs in specific hindwing banding pattern and forewing markings
Catocala verillianaCo-occurring underwing , smaller than C. amestris, with different hindwing coloration and pattern
Catocala epioneAnother yellow-orange hindwinged underwing, but with distinctively different forewing pattern and hindwing line arrangement

More Details

Conservation Status

Listed as endangered in Michigan with legal protection. Rarity attributed to specialized plant association with single (Amorpha), limiting suitability.

Survey Methods

Documented at stations using fermented fruit-beer-sugar mixture ('sugaring') during National Week events, suggesting this method may be more effective than light trapping for this .