Bug FAQMouse Moth
Amphipyra tragopoginis · Order: Lepidoptera · Family: Noctuidae
The mouse moth has a wingspan of about 3.2 to 4 cm and dark brown forewings marked with three blackish spots forming a triangle. It is found across much of Europe and parts of western Asia and flies from July to September in the British Isles. Its caterpillars feed on a wide range of plants, including many garden and tree species.
Source: Wikipedia
How to recognize it
The hindwings are a buff colour, getting darker toward the edges.
Source: Wikipedia
Size
The wingspan ranges from 32 to 40 mm.
Source: Wikipedia
Where it lives
It has a Holarctic distribution and is widespread across its range.
Source: Wikipedia
What it eats
The larvae are green with yellowish or white dorsal lines and eat many different plants.
Source: Wikipedia
Life cycle
The species overwinters as an egg.
Source: Wikipedia
When you see it
Adults are on the wing from July through September in the British Isles.
Source: Wikipedia
Where it is found in the US
Recorded in 24 of 51 states and DC. Most records: Michigan, Oregon, Montana, Idaho, Washington, Massachusetts, Vermont, Connecticut.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in United States; introduced in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When are mouse moths active?
In the British Isles adults fly from July to September.
Source: Wikipedia
What do mouse moth caterpillars look like?
The larvae are green with yellowish or white dorsal and subdorsal lines.
Source: Wikipedia
What plants do mouse moth larvae eat?
They feed on a wide variety of plants such as monkshood, chervil, dogbane, columbine, wormwood, bellflower, and many others.
Source: Wikipedia
Same family (Noctuidae)
Ipsilon Dart MothAgrotis ipsilonDamages trees, gardens or crops
Fall Armyworm MothSpodoptera frugiperdaDamages trees, gardens or crops
Army Cutworm MothEuxoa auxiliarisDamages trees, gardens or crops
Large Yellow UnderwingNoctua pronubaDamages trees, gardens or crops
Silver ΥAutographa gamma
American DaggerAcronicta americanaCan irritate skinSources
- Wikipedia: https://en.wikipedia.org/wiki/Mouse_moth
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-25 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-25.