E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Colias nastes Fabricius, 1807
Labrador Sulphur; Sulphurs
Family: Pieridae (Whites, Marbles, and Sulphurs)
Species account authors: Crispin Guppy and Jon Shepard.
Extracted from Butterflies of British Columbia
The Families of Lepidoptera of BC
Introduction to the Butterflies of BC
Photo of species

© Norbert Kondla  Email the photographer   (Photo ID #6178)

E-Fauna BC Static Map
Distribution of Colias nastes in British Columbia
Details about map content are available here.

Species Information


Adult

Arctic Sulphurs are slate grey, grey green, green, or green yellow with extensive black markings. This is the only sulphur in which males as well as females have light spots within the black wing border. The forewing colour ranges from entirely slate grey through green to nearly white, with the variation occurring within as well as between populations. Jon and Sigrid Shepard found an aberrant Arctic Sulphur with orange dorsal wings on Sweeney Mountain in the central Coast Range, as part of a population of normal Arctic Sulphurs.

Immature Stages

Mature larvae are dark green and have two pink-edged stripes down each side (Bird et al. 1995).

Subspecies

The subspecies that occurs in most of BC is Colias nastes streckeri Grum-Grschimailo, 1895 (TL: Laggan [vicinity of Lake Louise], AB). The dorsal wing colours are highly variable, but are generally dull yellow green, with poorly defined dark wing borders that include poorly defined pale spots. The submarginal dark spots on the ventral forewings are usually only faintly present. Subspecies aliaska Bang-Haas, 1927 (TL: Rampart, AK) occurs in extreme northwestern BC. The dorsal wing colours are highly variable, but are generally bright yellow green with dark wing borders containing well-defined pale spots. The submarginal dark spots on the ventral forewing are strongly developed.

Genus Description


Colias is the name of a promontory on the coast of Attica where there was a tem pie of Aphrodite. There is no obvious relationship to the butterfly, but the name may be a pun (Emmet 1991). An alternative explanation is suggested under Pontia. The common name "sulphurs" is derived from the yellow "sulphur" colour of most species.

Sulphurs in BC are generally medium-sized butterflies that are yellow, orange, white, or (one species) yellow green with black markings. The wings of males always have a solid black border, with the exception of the Arctic Sulphur. The black borders of females contain extensive pale areas, or may be greatly reduced or absent. There are several multivoltine species that show considerable seasonal variation in wing colour.

There are about 70 species of Colias in the world. The centre of distribution in North America is BC, with more species (13) than any other province or state. Colias species may all be inter-fertile, with natural hybrids known for most species combinations where they occur together in the wild. The species have behavioural, ecological, and physiological differences that maintain separation of the species in the wild (Hovanitz 1963).

Eggs are laid singly on the leaves of the foodplants, and are pale yellow green to cream, later turning orange. Young larvae are slender, yellowish or green, and smooth-skinned with a thin coat of fine hairs. Mature larvae are yellow green or green with fine black dots all over, and stripes of various colours running along the back and sides. Sulphurs hibernate as second to fourth instar larvae (except Canadian Sulphurs, which hibernate as fifth instar larvae), and then complete development in the spring. There are five larval instars in all Colias (Ae 1958a). Pupae are fastened head up with a girdle around the middle.

Members of the genus utilize a wide range of foodplants, although each species specializes to a greater or lesser extent. Larvae of sulphurs feed on plants in three groups: legumes (Fabaceae), Vaccinium (Ericaceae), and Salix (Salicaceae). Sulphurs occur in a wide range of habitats, including arid sagebrush areas, alfalfa fields, meadows, alpine tundra, and forest bogs.

Sulphurs always rest with their wings folded over their backs, and bask in the sun by leaning to the side to allow the sun to warm the underside of their wings. It has been demonstrated for several species (C. meadii, C. nastes, C. philodice, and C. eurytheme) that the darker the pigmentation on the underside of the wings, the more heat can be absorbed from the sun while basking, permitting greater flight activity in cold environments (Kingsolver 1985).

There is relatively little variation in wing pattern between many species, making identification difficult. The key characters mentioned in the species discussions are shown in the figure.

Biology


Arctic Sulphurs are univoltine, and fly in July and August. They fly low across dry alpine tundra, and when they land, they blend in perfectly with the short tundra vegetation. They are alert and difficult to approach, flying up and letting the wind whisk them out of sight when approached.

Larval foodplants are unknown for BC. In Manitoba and Alberta larval foodplants include Astragalus alpinus, Oxytropis campestris, and O. splendens (Klots 1975; Bird et at. 1995). In Europe Astragalus alpinus and A. deflexus are used (Petersen 1967; Higgins and Riley 1970).

Habitat


Arctic Sulphurs occur in alpine tundra across the mainland of southern BC. They are also known to occur on a few scattered mountains in northwestern BC, but are probably much more common there than our current inventory indicates.

Distribution

Distribution

Arctic Sulphurs occur across northern Eurasia and arctic North America. In western North America they occur through the mountains of BC and AB, south to extreme northern WA and MT.

Status Information

Scientific NameOrigin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
Colias nastesNativeS5YellowNot Listed
Colias nastes aliaskaNativeS4YellowNot Listed
Colias nastes streckeriNativeS5YellowNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Photo Sources

General References


Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-10-03 6:53:39 AM]
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