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New Jersey Endangered and Threatened Species Field Guide

Image of The Bronze copper is listed as endangered in New Jersey.Zoom+ The Bronze copper is listed as endangered in New Jersey. © Ron Hay

Bronze copper

Lycaena hyllus

Species Group: Invertebrate

Conservation Status

State: Endangered



The Bronze copper is one of the largest coppers. Adults reach 1.5 – 1.9 in. (37-47mm) in length. Male and female coppers have different colorings on the upper surface of their forewings. Males have a solid iridescent purple forewing. Females have orange forewings with a few black spots where only the forewing margin has a purple iridescence. Otherwise, the overall coloration of both sexes is orange.

Image of Range of the bronze copper in New Jersey.Zoom+ Range of the bronze copper in New Jersey.

Distribution and Habitat

In New Jersey the Bronze copper is rare. Its range is fairly widespread and it is found in most states above the Mason-Dixon Line. Its range extends into many Canadian Provinces.
Bronze coppers can be found in moist or wet areas, including brackish and freshwater marshes, bogs, fens, seepages, wet sedge meadows, riparian zones, wet grasslands, and drainage ditches.


Larvae or caterpillars feed on water dock (Rumex orbiculatus), curled dock (Rumex cripus), and knotweeds (Polygonum spp.) (Iftner et. al. 1992; Opler and Malikul 1998). Adults nectar on red clover (Trifolium pretense), milkweeds (Asclepias spp.), asters (Aster spp.), thistles (Cirsium spp.), and a variety of other herbs and grasses.

Life Cycle

Each summer the Bronze copper goes through two broods. Both generations of adults die after reproducing. Adults fly from mid-June to mid-September. Caterpillars are yellowish-green and have a dark dorsal stripe down their backs. They feed on water dock, curled dock, and knotweeds. The second generation of adults lay eggs that overwinter and hatch the next season.

Image of Bronze copper.Zoom+ Bronze copper. © Ron Hay

Current Threats, Status, and Conservation

Since the 1940s only a few individuals have been observed. Bronze coppers were once common and were scattered throughout the state, primarily in the northern regions of New Jersey. Habitat loss from the draining of wetlands and the use of herbicides and insecticides has seriously effected the population in New Jersey. This butterfly was listed as endangered in 2001. Wetland protection is key for long-term success of this species in New Jersey.


Iftner, D.C., J.A. Shuey, and J.V. Calhoun. 1992. Butterflies and Skippers of Ohio. Ohio Biological Survey Bulletin, new series, vol. 9 no. 1.
Opler, P.A., and V. Malikul. 1998. A Guide to Eastern Butterflies. New York: Houghton Mifflin.

Text derived from the book, Endangered and Threatened Wildlife of New Jersey. 2003. Originally written by David M. Golden. Originally edited by B.E. Beans & L. Niles. Edited and updated in 2010 by Ben Wurst.

Scientific Classification

Kingdom: Animalia
    Phylum: Arthropoda
       Class: Insecta
          Order: Lepidoptera
             Family: Lycaenidae
                Genus: Lycaena
                   Species: L. hyllus

Find Related Info: Endangered, Invertebrates

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