SPECIES FACT SHEET
Scientific Name: Colias occidentalis pseudochristina = Colias christina
psuedochristina
Common Name: Intermountain Sulphur
Phylum: Mandibulata
Class: Insecta
Order: Lepidoptera
Family: Pieridae
Note: Although this taxonomically unstable subspecies has been
classified differently by various authors (e.g. Pyle 2002, Warren 2005),
the most recent treatment by Pelham (2008) places it in the Colias
christina species, with which it shares the trait of having dorsal
ultraviolet reflective scales in some males.
Conservation Status:
Global Status (2006): G3G4T2T4
Rounded Global Status: G3 - Vulnerable
National Status (United States): NU- Unknown
State/Province Statuses: Idaho (SNR-State Not Ranked), Utah (SNR),
Washington (S1-Critically imperiled), Oregon (not evaluated)
(NatureServe 2009)
Technical Description:
Adult: Bright yellow or yellow-orange sulphur butterfly with black
dorsal front wing margins in males. This subspecies is identified as
follows (Pyle 2002, Warren 2005, Opler et al. 2006):
 Medium-sized; 4.5 - 6.3 cm (1.75 to 2.5 in.) wingspan
 Dorsal surface of the male yellow, with orange over-scaling in
96% of males
 Dorsal surface of some males with ultraviolet reflective scales
 Dorsal surface of female yellow to light cream or (rarely) white
 Front wing tips pointed
 Black margin on dorsal front wing narrow and solid in males,
and smudgy, broken or absent in females
 Ventral hind wing with a large, pearly spot with a reddish rim
Since there are no other subspecies of Colias christina (= occidentalis)
in the region, the most confounding species is the orange sulfur
(Colias eurytheme), which differs in having the ventral hind wing discal
spot double-ringed (as opposed to simple-ringed) (Hammond 2009,
pers. comm.). Additionally, while both C. christina pseudochristina and
C. eurytheme can have orange over-scaling, the orange color is more
limited and suffused in C. c. pseudochristina, without a central orange
patch on each wing (Pyle 2002).
Immature: The eggs, larvae, and pupae are difficult to find and to
identify. The immature stages of closely related C. occidentallis
sullivani (= C. christina sullivani) are described and figured in Harry
(2005).
Life History:
Depending on seasonal conditions, adults of this subspecies fly mostly
in late May (e.g. Asotin Co. Washington, 3400 ft.), but individuals have
been collected at higher elevations through late June (Minam River,
3000 ft.) and early July (upper Imnaha River, 4400 ft.). The flight
periods of both C. occidentalis and C. christina are from MaySeptember, peaking in June through July. Oblong eggs are laid singly
on the leaves of the host plant (see Neill 2001), and overwinter in the
larval stage. The larvae of this subspecies feed on Lathyrus species,
including L. brachycalix, L. lanzwertii, L. nevadensis, and L. puciflorus
(Hammond 2009, pers. comm.). The Asotin County population in
Washington was reported to feed on L. puciflorus (reviewed in Warren
2005). Adults of C. christina use a variety of plants as nectar sources,
and males may occasionally be seen frequenting mud puddles (Opler
et al. 2006). Nothing is known about colonization ability, but the
species appears to be a strong flier.
Range, Distribution, and Abundance:
Range-wide: The subspecies is found from the eastern Blue Mountains
in Washington, through the Blue and Ochoco Mountains in Oregon,
along the Snake River in Idaho, and south into western Utah. One
population is known in Washington, probably fewer than five
populations in Oregon, and unknown numbers in Idaho and Utah.
Washington: This subspecies is known from two townships in
southern Asotin County, on the Oregon border. The percentage of the
range that is occupied is unknown, and no population estimates are
available.
Oregon: Numerous locations in northeast Oregon, in the Ochoco,
Aldrich, Blue, and Wallowa mountains.
Federal Land: In Washington, this species is suspected on Umatilla
National Forest and Vale BLM District land. In Oregon, it is
documented from Wallowa-Whitman National Forest and suspected on
the Umatilla National Forest and BLM land in the Vale.
Habitat Associations:
This species inhabits open woodland from 1036 to 1524 m (3400 to
5000 ft.), including meadows, roadsides, and open forest. Warren
(2005) states that members of this subspecies are most often found on
steep sunny slopes at the ecotone between forest and shrubsteppe or
grassland habitats. Hammond (2009, pers. comm.) describes the
subspecies habitat as sagebrush with scattered Ponderosa Pine,
including both south- and east-facing slopes. The larvae of this
subspecies feed on Lathyrus species, including L. brachycalix, L.
lanzwertii, L. puciflorus, and. L. nevadensis (Hammond 2009, pers.
comm.). The Asotin County population in Washington was reported to
feed on L. puciflorus (reviewed in Warren 2005). Adults of C. christina
use a variety of plants as nectar sources, and males may occasionally
be seen frequenting mud puddles (Warren 2005).
Threats:
Loss of habitat due to agricultural conversion and development are the
primary threats to this species. Pesticide use also poses serious
threats, and aerial spraying of Btk (Bacillus thuringiensis var. kurstaki)
for forest defoliating moths has weakened and eliminated several
populations of this subspecies in eastern Oregon (Hammond 2009,
pers. comm.). Additionally, the widespread spraying of Dimilin,
pyrethroids, and organophosphates for grasshopper control occurs
yearly in the range of this species (ODA 2008, Walenta 2008), and may
pose further threats.
Conservation Considerations:
Inventory: Since there are relatively few records of this subspecies in
Oregon and Washington, and many of the existing populations have
been negatively influenced by Btk spraying (Hammond 2009, pers.
comm.), further surveys at known and potential sites will be valuable
in evaluating the taxonomic status, range, population characteristics,
and conservation needs of this subspecies.
Management: Provide protection of known and potential sites from
practices that would adversely affect any aspect of this butterfly’s lifecycle. Avoid insecticide/herbicide use in or near known sites and
manage grazing to reduce impacts to Lathyrus, the larval food plant.
Research: Although there are reasonable arguments for the current
taxonomic placement of this subspecies within C. christina, DNAsequence analysis of this subspecies and other members of C. christina
and C. occidentalis could elucidate the taxonomic placement of these
groups (Warren 2005).
Version 2:
Prepared by: Sarah Foltz
Xerces Society for Invertebrate Conservation
Date: June 2009
Edited by: Sarina Jepsen
Xerces Society for Invertebrate Conservation
Date: July 2009
Edited by: Rob Huff
FS/BLM-Conservation Planning Coordinator
Date: August 2009
Version 1:
Prepared by: John Fleckenstein
Natural Heritage Program
Washington Department of Natural Resources
Date: January 2006
Edited by: Rob Huff
Conservation Planning Coordinator
FS/BLM-Portland
Date: June 2007
ATTACHMENTS:
(1)
References
(2)
Maps of known sites in Oregon and Washington
ATTACHMENT 1:
References:
Dornfeld, E.J. 1980. The Butterflies of Oregon. Timber Press, Forest
Grove, Oregon. 276 pp.
Hammond, Paul. 2009. Personal communication with Sarah Foltz,
Xerces Society for Invertebrate Conservation.
Harry, J. 2005. Immature stages of Colias occidentalis sullivani from
Oregon (Lepidoptera: Pieridae). The Taxonomic Report 6(2): 1-4.
NatureServe. 2009. “Colias occidentalis pseudochristina.” NatureServe
Explorer: An online encyclopedia of life [web application]. Feb. 2008.
Version 7.0. NatureServe, Arlington, Virginia. 15 Feb. 2009.
<http://www.natureserve.org/explorer/>.
Neill, W. 2001. The guide to butterflies of Oregon and Washington.
Westcliffe Publishers, Englewood, Colorado. 160 pp.
Opler, P.A., Pavulaan, H., Stanford, R.E. and M. Pogue, coordinators.
2006. Butterflies and Moths of North America. Bozeman, MT: Big Sky
Institute. 9 Feb. 2009. <http://www.butterfliesandmoths.org/>.
Oregon Department of Agriculture (ODA). 2008. Oregon Grasshopper
and Mormon Cricket Survey Map. Oregon Department of Agriculture
(ODA) in Cooperation with USDA-APHIS-PPQ. Salem, Oregon.
Pelham, J. 2008. A catalogue of the butterflies of the United States
and Canada with a complete bibliography of the descriptive and
systematic literature. Journal of Research on the Lepidoptera 40: 658
pp.
Pyle, R.M. 2002. Butterflies of Cascadia. Seattle Audubon Society,
Seattle, Washington. 420 pp.
Walenta, D.L. 2008. Summary Report. Economic Impact of
Grasshopper Infestations to Agricultural Producers in Baker, Union,
and Wallowa County of Northeastern Oregon. Oregon State University
(OSU) Extension Service, Corvallis, Oregon.
Warren, A.D. 2005. Butterflies of Oregon: Their Taxonomy,
Distribution, and Biology. Lepidoptera of North America 6.
Contributions of the C.P. Gillette Museum of Arthropod Diversity.
Colorado State University, Fort Collins, Colorado. 408 pp.
ATTACHMENT 2:
Maps of known sites in Oregon and Washington
Records of Colias occidentalis pseudochristina in Washington and Oregon, relative to
Forest Service and BLM lands. The suspected distribution is based on known record
localities and personal communication with Paul Hammond (2009).