The bronze copper is large — for a copper. From above, males and females look quite different. Adult males, when fresh and young, shine with purplish-bronze iridescence on the upper side; later, they are mainly just brown with some undistinguished darker spots. The female upperside forewings are orange, with a brown outer margin and several dark spots. The hindwing upperside, in both sexes, is brown with a wide orange outer band. Viewed from below, there is no apparent difference in the sexes; both have a whitish hindwing and coppery orange forewing, both with scattered black spots. The hindwing outer margin has a wide orange band.
Caterpillars are short and sluglike, with a covering of soft, downy hairs; color is yellowish green with a darker green stripe down the back.
- The gray copper (L. dione) is grayish white, not orange, on the underside forewing, and adults of that species fly only into July, not later.
- The American copper (L. phlaeas) resembles the female bronze copper from above, but viewed from below, its hindwing underside orange band is much thinner than the bronze copper’s wide one. Also, the American copper is much smaller than the bronze, having a wingspan of only ¾–1 inch.
Wingspan: 1¼–1¾ inches.
Potentially statewide. It is widespread in well-established, localized breeding colonies in western and northern Missouri, but it is rare in the Ozarks.
Habitat and Conservation
This butterfly is usually found in wet pastures, prairies, and along weed railroad tracks, and similar low, wet, grassy, open areas. Males perch on low plants, watching for females, while both sexes visit flowers.
Caterpillars eat plants in genus Rumex, including curly (or yellow) dock (R. crispus). This species is also reported on various knotweeds (Polygonum spp.). Adults visit flowers for nectar, and they also take moisture and nutrients from puddles and other wet places on the ground.
There are at least two broods, with adults flying May through October. Males perch and patrol. Females deposit eggs singly on various parts of suitable larval food plant, especially flowers, flower buds, and stems. They overwinter as eggs. Like other members of this family, the short, thick pupae are attached to a leaf of the food plant by silk.
These butterflies, with their delicate patterns, orange color, and bright but fleeting iridescent purples and bronzes, delight us as they flit around wildflowers in sunny wetlands.
The caterpillars, feeding on the flowers and buds of their food plants, help to limit the growth and spread of docks and knotweeds. Adults play a role in pollination, and they also become food for several kinds of predators, ranging from grassland sparrows and bluebirds, which can spy them from afar, to crab spiders and assassin bugs, which ambush them as they visit flowers.