Western White
Pontia occidentalis (Reakirt, 1866)
Family: Pieridae
Subfamily: Pierinae
Identification: Upperside of forewing has marginal markings that are lighter than the submarginal stripe. Below, forewing tip and hindwing have veins outlined with gray-green. Short-day spring and fall forms have more prominent markings.
Wing Span: 1 1/2 - 2 1/8 inches (3.8 - 5.3 cm).
Life History: Males patrol hilltops and ridges for receptive females. Females lay eggs singly on host plants. Caterpillars will feed on leaves but prefer buds, flowers, and fruits. Chrysalids hibernate.
Flight: One flight from June-July in far north; two flights from May-August in the south.
Caterpillar Hosts: Flowers and fruits of various members of the mustard (Brassicaceae) family.
Adult Food: Flower nectar.
Habitat: Mountain peaks, slopes, hilltops, railroad yards, open plains, roadsides.
Range: Alaska south to central California, northern Arizona and northern New Mexico; east to North Dakota and central Ontario.
Conservation: Not usually required.
NCGR: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
Management Needs: None noted.
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Verified Sightings
Displaying 1 - 24 of 660 verified sightings
Observation date: Jun 11, 2024
Submitted by: RobSimpson
Region: Park County, Montana, United States
Verified by: J_Martineau
Verified date: Dec 02, 2024
Observation date: Aug 25, 2024
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Oct 19, 2024
Observation date: Jul 06, 2021
Submitted by: Buddy Mays
Region: Jefferson County, Oregon, United States
Verified by: John Calhoun
Verified date: Oct 07, 2024
Observation date: Aug 22, 2024
Submitted by: jthompson6112
Region: Blaine County, Idaho, United States
Verified by: stevekohler
Verified date: Sep 20, 2024
Observation date: Aug 25, 2024
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Sep 11, 2024
Observation date: Jul 29, 2024
Submitted by: ncrosbyrd
Region: Carbon County, Montana, United States
Verified by: J_Martineau
Verified date: Sep 04, 2024
Observation date: Jul 31, 2024
Submitted by: ncrosbyrd
Region: Carbon County, Montana, United States
Verified by: J_Martineau
Verified date: Sep 04, 2024
Observation date: Jul 26, 2024
Submitted by: Cascade Colors
Region: Grand County, Colorado, United States
Verified by: mikefisher
Verified date: Aug 26, 2024
Observation date: Jul 23, 2024
Submitted by: Cascade Colors
Region: Garfield County, Colorado, United States
Verified by: mikefisher
Verified date: Aug 26, 2024
Observation date: Jul 29, 2024
Submitted by: Robert Gorman
Region: Carbon County, Montana, United States
Verified by: J_Martineau
Verified date: Aug 11, 2024
Observation date: Jul 19, 2024
Submitted by: Robert Gorman
Region: Rich County, Utah, United States
Verified by: James Steen
Verified date: Aug 09, 2024
Observation date: Jul 06, 2024
Submitted by: dvollmar
Region: Custer County, South Dakota, United States
Verified by: J_Martineau
Verified date: Aug 08, 2024
Observation date: Jul 21, 2024
Submitted by: jrmbutterfly
Region: British Columbia, Canada
Verified by: jwileyrains
Verified date: Jul 29, 2024
Observation date: Jul 02, 2024
Submitted by: hasfitz5
Region: Washoe County, Nevada, United States
Verified by: Ken Davenport
Verified date: Jul 10, 2024
Observation date: May 28, 2024
Submitted by: mbfurr
Region: Harney County, Oregon, United States
Verified by: Ken Davenport
Verified date: Jun 06, 2024
Observation date: Aug 09, 2021
Submitted by: twofried
Region: Taos County, New Mexico, United States
Verified by: James Steen
Verified date: Jan 30, 2024
Observation date: Sep 02, 2023
Submitted by: rbuist
Region: Manitoba, Canada
Verified by: chalicerae
Verified date: Dec 09, 2023
Observation date: Sep 04, 2023
Submitted by: rbuist
Region: Manitoba, Canada
Verified by: chalicerae
Verified date: Dec 09, 2023
Observation date: Aug 26, 2023
Submitted by: NikkiM
Region: Carbon County, Montana, United States
Verified by: J_Martineau
Verified date: Nov 06, 2023
Observation date: Jul 04, 2023
Submitted by: katb1
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Sep 28, 2023
Observation date: Aug 25, 2023
Submitted by: Pandy
Region: Alberta, Canada
Verified by: Paul Prappas
Verified date: Sep 28, 2023
Observation date: Sep 13, 2023
Submitted by: RoxannaTessman
Region: Klamath County, Oregon, United States
Verified by: Ken Davenport
Verified date: Sep 14, 2023
Observation date: Aug 12, 2023
Submitted by: NikkiM
Region: Carbon County, Montana, United States
Verified by: stevekohler
Verified date: Sep 12, 2023
Observation date: Sep 04, 2023
Submitted by: MrRod
Region: Saskatchewan, Canada
Verified by: alchem30
Verified date: Sep 09, 2023
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