Bug FAQWestern White
Pontia occidentalis · Order: Lepidoptera · Family: Pieridae
The Western White butterfly has a wingspan of about 38 to 53 mm. It lives in western North America, where its caterpillars feed on mustard-family plants, especially the flowers, buds and fruit. In the northern part of its range adults fly in June and July, while in the south there are two generations from May to August.
Source: Wikipedia
How to recognize it
The upper side of the forewing shows lighter marginal markings compared with the sub-marginal stripe. On the underside, the tips of the forewings and the hindwings have veins outlined in gray-green.
Source: Wikipedia
Size
Its wingspan ranges from 38 to 53 mm.
Source: Wikipedia
Where it lives
It is found in western North America.
Source: Wikipedia
What it eats
Caterpillars feed on plants in the mustard or cabbage family, Brassicaceae. They especially eat the flowers, buds and fruit of those host plants.
Source: Wikipedia
Life cycle
In the north, one generation flies in June and July.
Source: Wikipedia
When you see it
Northern populations are on the wing in June and July. Southern populations have two flight periods from May through August.
Source: Wikipedia
Where it comes from
Its native range is western North America.
Source: Wikipedia
Lookalikes
It is found in western North America, the same region where similar species may occur.
Source: Wikipedia
Where it is found in the US
Recorded in 21 of 51 states and DC. Most records: Alaska, Idaho, Oregon, Colorado, Washington, California, Montana, Utah.
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
Questions people ask
What plants do Western White caterpillars eat?
They feed on mustard-family plants, especially the flowers, buds and fruit.
Source: Wikipedia
When are Western White butterflies active?
In the north they fly in June and July; in the south there are two generations from May to August.
Source: Wikipedia
Same family (Pieridae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Pontia_occidentalis
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.