Bug FAQOnce-married Underwing
Catocala unijuga · Order: Lepidoptera · Family: Erebidae
Also called: Oncemarried Underwing, Once-married Underwing Moth
The once-married underwing is a medium-sized moth with a wingspan of about 68 to 82 mm. It is found across much of North America and its caterpillars feed on aspen, poplar and willow species. Adults are on the wing from July to September, producing a single generation each year.
Source: Wikipedia
How to recognize it
The once-married underwing belongs to the moth family Erebidae.
Source: Wikipedia
Size
Its wingspan measures roughly 68 to 82 mm, or about 2.7 to 3.2 inches.
Source: Wikipedia
Where it lives
It lives across North America, from Newfoundland west to central British Columbia and south to Kentucky, Missouri, Colorado and Utah.
Source: Wikipedia
What it eats
The larvae feed on trembling aspen, black poplar and various willow species.
Source: Wikipedia
Life cycle
Adults are active from July through September, with one generation per year.
Source: Wikipedia
When you see it
The flight period for adults spans July to September, depending on location.
Source: Wikipedia
Where it comes from
Its native range covers the same area: Newfoundland to central British Columbia, and south to Kentucky, Missouri, Colorado and Utah.
Source: Wikipedia
Where it is found in the US
Recorded in 31 of 51 states and DC. Most records: Michigan, Minnesota, New York, Maine, Massachusetts, Wisconsin, Connecticut, Vermont.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Same family (Erebidae)
Spongy MothLymantria disparDamages trees, gardens or crops
Fall Webworm MothHyphantria cuneaDamages trees, gardens or crops
Brown-tail MothEuproctis chrysorrhoeaCan irritate skin
Isabella Tiger MothPyrrharctia isabella
Virginian Tiger MothSpilosoma virginicaCan irritate skin
Salt Marsh MothEstigmene acreaSources
- Wikipedia: https://en.wikipedia.org/wiki/Catocala_unijuga
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.