Endangered Resources Program Species Information
Dorcas Copper (Lycaena dorcas)

Dorcas Copper Photo by Mike Reese. Check the photos tab for additional photos.
Photo © Mike Reese

Overview

Species Overview

Dorcas copper (Lycaena dorcas), a State Special Concern butterfly, has been found in boreal rich fens, wet meadows, lake margins, bogs and poor fens, tamarack and black spruce swamps. Shrubby cinquefoil (Pentaphylloides floribunda) is commonly used as the host plant in the Great Lakes area and appears to be the foodplant of Door County populations. However, most L. dorcas sites in Wisconsin contain no shrubby cinquefoil and the butterfly is closely associated with marsh cinquefoil (Comarum palustra). Adults fly from about July 1 into early August in Wisconsin or as early as mid June during years with an early spring.

Status and NHI Documented Occurrences in Wisconsin

The table below provides information about the protected status (State and Federal Status) and the rank (S and G Ranks) for Dorcas Copper (Lycaena dorcas). See the Working List Key for more information about the abbreviations used. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. For invertebrates, dots depict locations from the "Invertebrate Atlas," a database with occurrences of rare and common aquatic and select terrestrial invertebrate species found in Wisconsin and adjacent areas. While the invertebrate atlas is a quality assured database, not all records have been verified. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Summary Information
State Status:	SC/N
Federal Status in Wisconsin:	none
State Rank:	S1S2
Global Rank:	G5
Tracked by NHI:	Y
Species of Greatest Conservation Need:

Documented locations of Lycaena dorcas in the Natural Heritage Inventory Database as of April 2009.

Detailed Information

Identification: A small copper with brown uppersides and scattered black spots with a bit of orange at the lower margin of the hindwing. Males exhibit a purple sheen of varying intensity. Females have varying amounts of orange on the forewing above, particularly after the postmedian spots. The underside of the forewing is dull orange with black spots. The hindwing below is orangish-gray with a jagged submarginal orange line. Extent of black spots on the upperside and ground color of the underside helps to distinguish this species from the bog copper (Lycaena epixanthe). Because of variability and similarity of other copper species, records should preferably be documented with voucher specimens. Good close-up photos of both upper and underside may be acceptable, but accurate identification is not always possible. Wingspan: 24-27mm. Length of forewing: 13-14 mm. Larvae have a tan head and pale green body with white hairs, white oblique dashes on the sides and a green midline.

Similar Species: Males of the purplish copper (L. helloides) are very similar but have more submarginal orange extending along most of the outer margin. Female purplish coppers are predominantly bright orange above. The bog copper is silvery below.

Habitat: Boreal rich fens, wet meadows, lake margins, bogs and poor fens, tamarack and black spruce swamps.

Nectar Source: Cinquefoil and cranberry (Vaccinium spp.) in Wisconsin.

Host Plant: Shrubby cinquefoil (Pentaphylloides floribunda) is commonly used in the Great Lakes area and appears to be the foodplant of Door County populations. However, most L. dorcas sites in Wisconsin contain no shrubby cinquefoil and the butterfly is closely associated with marsh cinquefoil (Comarum palustra).

Associated Species: Sometimes occurs with the bog copper.

State Distribution: Populations are localized. Documented from Door, Douglas, Forest, Iron, Langlade, Lincoln, Marathon, Oneida, Rusk, Sawyer, and Vilas counties.

Global Distribution: Abundant in the western Canadian provinces north to the Yukon and scattered eastward to Newfoundland.

Threats: Loss of wetland habitat and disruption of hydrology.

Phenology: Adults fly from about July 1 into early August in Wisconsin or as early as mid June during years with an early spring.

Life History: Univoltine. Eggs are laid singly on the underside of cinquefoil leaves. The leaves drop to the ground in the fall and eggs overwinter on the ground (Opler et al. 1995). Larvae hatch in the spring and crawl to the hostplant to feed. There are five larval stages (Opler and Krizek 1984). With many of the Lycaenids, fully developed larvae overwinter within the egg case, emerging in spring (Borkin, pers. comm.).

Survey Guidance: Stays near the foodplant. Males patrol and perch on the foodplant in search of females. New county records should be documented with voucher specimens.

Inventory, Monitoring and Research Needs: Locate additional populations. A considerable amount of potential habitat in Wisconsin has not been surveyed. There are likely a significant number of undiscovered populations throughout northern Wisconsin.

Information originally presented as part of the Online Field Guide to Rare Lepidoptera: Bogs and Barrens.

Photos

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