Glaucopsyche piasus

(Boisduval, 1852)

Arrowhead Blue

Glaucopsyche piasus, commonly known as the arrowhead blue, is a western North American in the Lycaenidae. It is locally common in prairie and open woodland , where are active from March through July. The is notable for its distinctive hindwing pattern featuring white arrowhead-shaped markings. Larvae develop on lupine (Lupinus) and milkvetch (Astragalus) plants.

BLUE, ARROWHEAD (Glaucopsyche piasus) (6-16-11) carcass cr, wayne co, ut - 04 (9424881256) by ALAN SCHMIERER. Used under a CC0 license.BLUE, ARROWHEAD (Glaucopsyche piasus) (6-16-11) carcass cr, wayne co, ut - 03 (9424880628) by ALAN SCHMIERER. Used under a CC0 license.NovaraExpZoologischeTheilLepidopteraAtlasTaf35 by Felder. Used under a Public domain license.

Pronunciation

How to pronounce Glaucopsyche piasus: //ɡlɔːˈkɒpsɪki ˈpaɪəsəs//

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Identification

Distinguished from similar blues by the prominent white arrowhead-shaped band on the hindwing underside. Males patrol near plants during daylight hours. Females can be observed laying on flower buds of lupine or milkvetch. The checkered wing fringes and violet-blue upper wing coloration in males are additional diagnostic features.

Images

Appearance

Wingspan ranges from 2.9 to 3.5 cm. Upper side of males is violet blue with a wide dark border; females are duller with reduced blue coloration. Underside of wings is gray with numerous small black spots. Hindwing underside displays a distinctive post- band of white arrowhead-shaped markings pointing inward. Wing fringes are checkered.

Habitat

Prairie, open woodland, and woodland edges and trails. Favors areas with abundant lupine or milkvetch plants.

Distribution

Western North America. Recorded from Alberta and Saskatchewan in Canada southward through the western United States.

Seasonality

One annually. active from March to July, with timing varying by latitude and elevation.

Diet

Larvae feed on lupine (Lupinus ) and milkvetch (Astragalus species). feed on flower nectar.

Host Associations

  • Lupinus - larval plantlarvae feed on lupine
  • Astragalus - larval plantlarvae feed on milkvetch

Life Cycle

One per year. Females lay on flower buds of plants. Larval development occurs on Lupinus and Astragalus. and stage not described in available sources.

Behavior

Males patrol during daylight hours near plants to locate females. Females oviposit on flower buds of host plants.

Ecological Role

as . Larval herbivore on leguminous plants. Specific interactions not documented.

Human Relevance

None documented.

Similar Taxa

  • Glaucopsyche lygdamusSimilar size and blue coloration; distinguished by hindwing pattern lacking arrowhead markings
  • Glaucopsyche alexisPalaearctic with similar ; not sympatric
  • Glaucopsyche melanopsPalaearctic ; hindwing pattern differs

Sources and further reading