Sulfurs: Labrador Sulfur (Colias nastes)
(Arthropoda: Insecta: Lepidoptera: Pieridae: Coliadinae)
Profile prepared by Sarah Foltz Jordan and Julia Janicki, The Xerces Society for Invertebrate Conservation
The Labrador Sulfur is a small species of sulfur of green wings with a tint of yellow and white on the upper side, and with light spots in the black wing border. It is a univoltine species and the numbers peak around July or August. It is a circumpolar species that inhabits high elevation wind swept tundra ridges; in North America, it ranges from much of Canada and Alaska, south to the Rocky Mountains and the Cascade Mountains. At this point, global climate change poses the greatest threat to this species.
National Statuses: United States (N5), Canada (N5)
State/Province Statuses: Montana (S2S3), Washington (S2S3), Alberta (S4), British Columbia (S5), Labrador (S3), Manitoba (S5), Northwest Territories (SNR), Nunavut (SNR), Quebec (S5), Yukon Territory (S5)
Immature: The larvae of this species are dark moss-green with two red-edged stripes down each side (Pyle 2002). The eggs and pupae are difficult to find and to identify.
Washington: In Washington, this species is known only from a narrow strip along the Canadian border in the western Okanogan Highlands, Okanogan County (Pyle 2002).
BLM/Forest Service Lands: This species is documented on Okanogan-Wenatchee National Forest.
The last known record of this species in Washington is from 1984, and most sites have not been revisited since the 1960’s or 1970’s. Revisit all known Washington sites and new sites with appropriate habitat, and survey for this species. Since abundance estimates for this species are not known, measure larval and adult abundance by conducting a timed visual search along transects through suitable habitat where food plants for caterpillars and nectar plants for adults are present (Miller and Hammond 2007).
Management: Protect and maintain habitat at sites where this species has been documented, including sufficient densities of the species’ host plants.
Guppy, C.S. and J.H. Shepard. 2001. Butterflies of British Columbia. UBC Press, Vancouver, British Columbia, 414 pp.
Miller, J.C. and P.C. Hammond 2007. Butterflies and moths of Pacific Northwest forests and woodlands. Forest Health Technology Team. 234 pp.
NatureServe. 2009. “Colias nastes”. NatureServe Explorer: An online encyclopedia of life [web application]. NatureServe, Arlington, Virginia. Version 7.1. (2 February 2009). Data last updated: February 2009. Available at: www.natureserve.org/explorer (Accessed 25 August 2010).
Opler, P.A., Lotts, K. and T. Naberhaus, coordinators. 2010. Butterflies and Moths of North America. Bozeman, MT: Big Sky Institute. Available at: www.butterfliesandmoths.org (Accessed 15 August 2010).
Pyle, R.M. 2002. The Butterflies of Cascadia. A Field Guide to all the Species of Washington, Oregon, and Surrounding Territories. Seattle Audubon Society. 420 pp.
Scott, J. 1986. The Butterflies of North America. Stanford University Press, Stanford, CA. 583 pp.