Butterflies and Moths of North America

collecting and sharing data about Lepidoptera

Acmon Blue
Plebejus acmon (Westwood, [1851])


Family: Lycaenidae
Subfamily: Polyommatinae
Identification: Upperside of males blue with dark narrow border; female brown. Underside white with black spot pattern. Hindwing above and below with red-orange submarginal band.
Wing Span: 3/4 - 1 1/8 inches (2 - 2.9 cm).
Life History: Males patrol near hosts for females. Eggs are laid singly on leaves or flowers of host plants. Caterpillars feed on leaves, flowers, and developing seeds, and are tended by ants. Second-stage caterpillars hibernate.
Flight: Many flights from March-October.
Caterpillar Hosts: Various species of buckwheats (Eriogonum nudum), lupines (Lupinus), trefoils (lotus), and milkvetches (Astragalus).
Adult Food: Flower nectar.
Habitat: Desert, fields, prairie hills, weedy areas, road edges.
Range: Primarily California west of Sierra Nevada-Cascade Divide south to northern Baja California. Precise limits in neighboring Oregon and Nevada not ascertained.
Conservation: Not usually of conservation concern.
NCGR: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
Management Needs: None reported.
Comments: NULL