Lange’s Metalmark Butterfly The Lange’s metalmark (Apodemia mormo langei) is a tiny butterfly found only at the Antioch Dunes. Their short lives are closely connected to their larval food plant, the Antioch Dunes buckwheat (Eriogonum nudum psychicola), which provides a place for adult butterflies to perch and nectar, to lay their eggs, and as a source of food for growing caterpillars. Adult butterflies are little bigger than a quarter and live for no more than a few weeks, resulting in a flight season of about a month in late summer. In that time, adult butterflies mate and deposit their eggs on the stems of withering buckwheat leaves in twos and threes.
With the rainy season, knobby, bristle-haired, lilac-colored caterpillars emerge. The caterpillars crawl to the base of the buckwheat and feed at night on the buckwheat’s tender new leaves until the time comes to overwinter. In the spring and summer, the caterpillars begin feeding again on new leaves and flowers, growing until they are ready to shed their skin and form a chrysalis. Inside, the caterpillars develop into butterflies. The Lange’s metalmark butterfly has a distinctive, erratic flight pattern, and is restricted to short flight distances (100 to 1,300 feet) marked by figure eights.
Lange’s Metalmark Butterfly Listing Status: Federally Endangered