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Cercyonis sthenele Scudder, 1875
Great Basin Wood Nymph; Woodnymphs
Family: Nymphalidae (Brushfoots)
Species account authors: Crispin Guppy and Jon Shepard.
Extracted from Butterflies of British Columbia.
Introduction to the Butterflies of BC
The Families of Lepidoptera of BC

Photograph

© Norbert Kondla     (Photo ID #8074)

Map

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Distribution of Cercyonis sthenele in British Columbia.
(Click on the map to view a larger version.)
Source: Butterflies of British Columbia by Crispin Guppy and Jon Shepard © Royal BC Museum

Species Information


Adult

Great Basin Wood nymphs are similar to Common Wood nymphs in having two well-defined eyespots on the forewings, but the rear eyespot is smaller than the front eyespot. The difference in eyespot size is sometimes very small, and is most easily seen on the underside of the wings. The outer part of the ventral hindwings is much lighter than the inner half of the wings, with a strong dark line separating the two areas.

Immature Stages

Eggs are cream-coloured, and nearly spherical with light but regular sculpturing. Mature larvae are light green with a dark green dorsal stripe and whitish lateral stripes. The head and body are covered with fine white hairs. There are two reddish anal tails. Pupae are olive green (Ferris and Brown 1981). The colour of the stripes is geographically variable, ranging from dark green to yellow or white (Emmel 1969).

Subspecies

The subspecies found in BC is C.s. sineocellata Austin and Emmel, 1998 (TL: west side of Crump Lake, 8.2 rd. mi. north of Adel, Lake Co., OR).

Genus Description


The name Cercyonis is derived from Cercyon, the son of Poseidon (Opler and Krizek 1984). The common name "woodnymphs" was first used by Holland (1898) in reference to the butterflies' bouncy flight in generally open forest habitat, similar to nymphs bounding through open forests.

Woodnymphs are medium-sized, dark brown butterflies with prominent eyespots on the forewings and sometimes smaller eyespots on the hindwings. The eyespots are usually larger in females than in males, and are set in a lighter band. Woodnymphs have a peculiar bouncing flight, similar to that of ringlets.

Eggs are laid singly on grass blades. They are pale yellow, becoming tan and mottled with orange brown as they mature. They are cylindrical and squat, with a flat top and ridges down the side. First instar larvae are thinly covered with thick curved hairs, and are green with light and dark longitudinal stripes. Mature larvae are slender, green, or yellow green, with light and dark longitudinal stripes down the back and sides. They are thinly covered with hairs, and have two short red tails. Pupae are roughly cylindrical, rounded, and suspended from a cremaster. They are green to yellow green, and in most species have white or yellow markings (Emmel 1969).

Eggs hatch about 10 days after oviposition (at 25°C), and the first instar larvae immediately enter hibernation. By spring the larvae have shrunk to half their original length before they come out of hibernation. Once they commence feeding, they primarily feed at night. There are five (oetus, sthenele) or six (pegala) larval instars. It takes oetus about 2 months to pupate in the wild, and sthenele and pegala 2.5-3 months. Pupation occurs near the base of a grass clump, with the pupa hanging from grass blades. Adults emerge after about 20 days (EmmeI 1969).

Biology


Great Basin Woodnymphs are univoltine and fly in June and July at low elevations, and in August above timberline. There are five larval instars, and a female lays 100-150 eggs (Emmel 1969). Great Basin Wood nymphs are uncommon in BC. The larvae presumably feed on grasses, probably bunchgrass because it is the most abundant grass in their habitat. Poa species is reported as a larval foodplant by Ferris and Brown (1981).

Habitat


Great Basin Wood nymphs occur in widely dispersed populations in dry low-elevation sagebrush, ponderosa pine, and Douglas-fir habitats in the southern and central interior. One population occurs above timberline in subalpine sagebrush grassland on Crater Mountain, near Keremeos. The three map records in Layberry et al. (1998) for the Kootenays are incorrect, and resulted from misidentifications of Small Woodnymphs.

Distribution

Distribution

Great Basin Woodnymphs are found throughout most of the dry areas of western North America.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
COSEWIC
NativeS4YellowNot Listed



BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

General References