Western Sulphur
Colias occidentalis Scudder, 1862
Family: Pieridae
Subfamily: Coliadinae
Identification: Upperside of male bright yellow with wide black border; orange morph is orange with yellow at costa and wing bases. Female pale yellow to greenish white with border blurry, incomplete, or absent; orange morph dull orange with wide black borders and dark veins. Underside of both sexes with pink wing fringes and golden yellow hindwing; orange morph green-gray to orange; both with dark overscales.
Wing Span: 1 3/4 - 2 1/2 inches (4.5 - 6.3 cm).
Life History: Males patrol in valleys or open areas near host plants for females. Females lay eggs singly on host plant leaves. Late-stage caterpillars hibernate.
Flight: May-August, mainly June-July.
Caterpillar Hosts: Plants of the pea family (Fabaceae) including vetch (Vicia angustifolia), sweet vetch (Hedysarum), lupines (Lupinus), and white sweet clover (Melilotus alba).
Adult Food: Flower nectar.
Habitat: Open areas including meadows, sagebrush flats, conifer forest openings, power-line cuts.
Range: Extreme southern British Columbia and northwestern United States south to north coastal California and central Utah.
Conservation: Some populations affected by grazing and fire suppression.
NCGR: G3, G4 - Very rare or local throughout its range or found locally in a restricted range OR Apparently secure globally, though it might be quite rare in parts of its range, especially at the periphery. Subspecies chrysomelas is T2,T3 and is threatened by fire suppression, improper logging, and invasive alien weeds.
Management Needs: Not reported.
Comments: NULL
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Verified Sightings
Displaying 25 - 48 of 161 verified sightings
Observation date: Jun 17, 2019
Submitted by: Vickie J Anderson
Region: Kittitas County, Washington, United States
Verified by: davidwdroppers
Verified date: Jun 21, 2019
Observation date: Jul 28, 2018
Submitted by: weflybye
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 29, 2018
Observation date: Jul 21, 2018
Submitted by: weflybye
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 21, 2018
Observation date: Jul 16, 2017
Submitted by: Paul Prappas
Region: Kittitas County, Washington, United States
Verified by: davidwdroppers
Verified date: Oct 02, 2017
Observation date: Jul 02, 2016
Submitted by: MTmariposa
Region: Missoula County, Montana, United States
Verified by: J_Martineau
Verified date: Aug 05, 2016
Observation date: Jun 23, 2013
Submitted by: MTmariposa
Region: Missoula County, Montana, United States
Verified by: J_Martineau
Verified date: Aug 14, 2013
Observation date: May 30, 2012
Submitted by: kayjon50
Region: Kittitas County, Washington, United States
Verified by: davidwdroppers
Verified date: Dec 17, 2012
Observation date: Jul 09, 2011
Submitted by: js97032@yahoo.com
Region: Wheeler County, Oregon, United States
Verified by: danaross
Verified date: Jan 23, 2012
Observation date: Jul 14, 2008
Submitted by: ryDLar
Region: Clark County, Washington, United States
Verified by: davidwdroppers
Verified date: Nov 22, 2011
Observation date: Jun 26, 2011
Submitted by: davidwdroppers
Region: Chelan County, Washington, United States
Verified by: davidwdroppers
Verified date: Jun 29, 2011
Observation date: Jun 13, 1982
Submitted by: legacy.reporter (Jim Brock)
Region: Lake County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: May 01, 2011
Observation date: May 30, 1981
Submitted by: legacy.reporter (unknown)
Region: Lake County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: May 01, 2011
Observation date: Jul 03, 2001
Submitted by: Norbert Kondla
Region: British Columbia, Canada
Verified by: Norbert Kondla
Verified date: Feb 11, 2011
Observation date: Jul 14, 2010
Submitted by: legacy.reporter (Paul Opler and EviBuckner-Opler )
Region: Okanogan County, Washington, United States
Verified by: paulopler (Paul Opler)
Verified date: Dec 31, 2010
Observation date: Jul 16, 2010
Submitted by: legacy.reporter (Paul Opler and EviBuckner-Opler )
Region: Madison County, Montana, United States
Verified by: paulopler (Paul Opler)
Verified date: Dec 31, 2010
Observation date: Jul 16, 2010
Submitted by: legacy.reporter (Paul Opler and EviBuckner-Opler )
Region: Madison County, Montana, United States
Verified by: paulopler (Paul Opler)
Verified date: Dec 31, 2010
Observation date: Jul 18, 2010
Submitted by: legacy.reporter (Paul Opler and EviBuckner-Opler )
Region: Fremont County, Idaho, United States
Verified by: paulopler (Paul Opler)
Verified date: Dec 31, 2010
Observation date: Jun 18, 1977
Submitted by: legacy.reporter (A. M. Shapiro)
Region: Trinity County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: Aug 03, 2010
Observation date: Jul 18, 1977
Submitted by: legacy.reporter (A. M. Shapiro)
Region: Trinity County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: Aug 03, 2010
Observation date: unknown
Submitted by: legacy.reporter (Sterling Mattoon)
Region: Siskiyou County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: Aug 03, 2010
Observation date: Jul 13, 1991
Submitted by: legacy.reporter (Ken Hansen, Scott North)
Region: Humboldt County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: Aug 02, 2010
Observation date: Jun 20, 1991
Submitted by: legacy.reporter (P. M. Thompson)
Region: Colusa County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: Aug 02, 2010
Observation date: Aug 12, 1990
Submitted by: legacy.reporter (Scott North)
Region: Humboldt County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: Aug 02, 2010
Observation date: Jun 01, 1990
Submitted by: legacy.reporter (J. B. Vernon)
Region: Colusa County, California, United States
Verified by: Ken Davenport (Ken Davenport)
Verified date: Aug 02, 2010
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