Bug FAQMountain Fritillary
Boloria napaea · Order: Lepidoptera · Family: Nymphalidae
Also called: Montain Fritillary
The mountain fritillary has a wingspan of about 35 to 48 mm and its upper wings are orange with brown markings and a line of round dots near the edge. It lives in alpine and sub-alpine areas of the European Alps, northern Scandinavia, the eastern Pyrenees, as well as Alaska, north-western Canada and parts of the Rocky Mountains. Caterpillars feed on violet species such as Viola biflora and on Polygonum plants, while adults are on the wing from June to August depending on location.
Source: Wikipedia
How to recognize it
The upper side of the wings is orange with brown designs, small scallops and a sub-marginal row of round dots. The hindwing has a distinct angle at its front edge.
Source: Wikipedia
Size
Wingspan ranges from 35 to 48 mm.
Source: Wikipedia
Where it lives
In Europe it inhabits the Alps, mountainous northern Scandinavia and the eastern Pyrenees. In North America it occurs in Alaska, north-western Canada and isolated spots in the Canadian Rockies, Alberta and Wyoming.
Source: Wikipedia
What it eats
Larvae feed on violet species, especially Viola biflora, and on Polygonum viviparum in Europe. In North America the larvae also use Polygonum bistortoides as a food plant.
Source: Wikipedia
Life cycle
Adults are active from June through August, timing varying with location.
Source: Wikipedia
When you see it
Flight period spans June to August depending on where they live.
Source: Wikipedia
Where it comes from
Native to European alpine regions and to parts of North America including Alaska and north-western Canada.
Source: Wikipedia
Where it is found in the US
Recorded in 3 of 51 states and DC. Most records: Wyoming, Alaska, Idaho.
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 are mountain fritillaries active?
Adults fly from June to August, with exact timing depending on the region.
Source: Wikipedia
What do the caterpillars eat?
They feed on violet species such as Viola biflora and on Polygonum plants, including Polygonum viviparum in Europe and Polygonum bistortoides in North America.
Source: Wikipedia
Same family (Nymphalidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Boloria_napaea
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-28 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-28.