Bronze copper

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.

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.

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.