Bug FAQRannoch Looper Moth and Allies
Macaria brunneata · Order: Lepidoptera · Family: Geometridae
Also called: Rannoch Looper, Rannoch Looper Moth
The Rannoch Looper Moth has a wingspan of about 25 to 30 mm and forewings 11 to 13 mm long. It lives in mature forests across Europe, Siberia, Japan, and northern mountainous parts of North America, especially central Scotland in Britain. Caterpillars eat bilberry in Britain and also bearberry and other heath-family plants in North America, and the adults fly in early summer (June-July in Britain, July-August in North America).
Source: Wikipedia
How to recognize it
It is a day-flying moth that often rests with its wings closed, like a butterfly.
Source: Wikipedia
Size
The wingspan ranges from 25 to 30 mm. Each forewing measures 11 to 13 mm in length.
Source: Wikipedia
Where it lives
In Britain it is mostly found in mature forests of central Scotland. Across its range it inhabits Siberia, Japan, northern and mountainous North America, and much of Europe.
Source: Wikipedia
What it eats
The caterpillars feed on bilberry in Britain. In North America they also eat bearberry and other heath-family plants.
Source: Wikipedia
Life cycle
Adults are on the wing in June and July in Britain. In North America they fly in July and August.
Source: Wikipedia
When you see it
The flight period is June-July in Britain and July-August in North America.
Source: Wikipedia
Where it is found in the US
Recorded in 16 of 51 states and DC. Most records: Alaska, Montana, Wyoming, Michigan, Maine, Massachusetts, Minnesota, Colorado.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
When can I see the Rannoch Looper Moth?
In Britain the moth flies in June and July, while in North America it is active in July and August.
Source: Wikipedia
What do the caterpillars eat?
They feed on bilberry in Britain and on bearberry and other heath-family plants in North America.
Source: Wikipedia
Same family (Geometridae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Macaria_brunneata
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-24.