FAMILY: Lycaenidae

DESCRIPTION: Adult Hermes copper butterflies have a wingspan between one and 1.25 inches. Upperside forewings are brown with yellow, brown-spotted centers; upperside hindwings are also brown and have a small tail with yellow within it. Underside forewings and hindwings are yellow with brownish spots. Mature larvae are about 13 millimeters and are an apple-green color, with a middorsal band of darker green bordered by yellowish green.

HABITAT: The Hermes copper is dependent for survival on its spiny redberry host plant, common in cismontane California coastal sage scrub and chaparral vegetation communities. But for unknown reasons, the butterfly is restricted to only a small portion of the redberry range. It generally appears to utilize redberry stands growing in deeper, well-drained soils of canyon bottoms and north-facing hillsides, with host and nectar plants intermixed or in close proximity.

RANGE: The Hermes copper ranges over 150 miles, from the vicinity of Fallbrook in northern San Diego County south to near Santo Tomás in Baja California, Mexico. The butterfly occupied many coastal areas prior to urbanization, and still occupies foothill and mountain areas up to 45 miles from the ocean at Pine Valley, California.

MIGRATION: The species has no observable tendency to migrate or otherwise stray from colonies, although there is presumed to be some intercolony movement, probably by the males.

BREEDING: Males perch to watch for females. Eggs are laid singly on stems of the host plant.

LIFE CYCLE: Winter diapause, or dormancy, occurs during the egg stage. Larvae hatch and mature through five instars over about 14 days, with larvae feeding on the leaves of the redberry host. Pupation occurs at the base of the redberry over a period of 10 to 14 days.

FEEDING: Larvae eat redberry leaves; adults primarily eat the nectar of the buckwheat plant, but have also been observed nectaring on chamise, golden yarrow, slender sunflower, poison oak, and short-podded mustard.

THREATS: The Hermes copper is threatened by urban development, overly frequent wildfire and prescribed fire, and global climate change.

POPULATION TREND: Only 15 populations of the Hermes copper are known to remain in existence in the United States following the large San Diego County fires of 2003. Three other populations in Baja California are presumed extant, but their actual status is unknown.

Photo © Douglas Aguillard