Golden hairstreak (Habrodais grunus herri)

Physical description

The Lycaenidae butterfly family consists of small and often brightly colored species with the common names: copper, hairstreak, elfin, and blue. 

Ecology and life history

The golden hairstreak is confined to the few small patches of its hostplant, the golden chinquapin (Chrysolepis chrysophylla), a broadleaf evergreen tree that occurs in low to middle elevations in southern Skamania County, the northern extent of the species’ range. The golden hairstreak spends much of its adult life, and all of its egg, larval, and pupal life stages in the open forest canopy of chinquapins. Small, adjacent forest openings in this landscape often provide additional floral nectar sources and puddling sites. Beyond their golden chinquapin host requirement, little is known of their habitat needs.

This lycaenid butterfly completes a single life cycle annually (univoltine). All lycaenids are sedentary butterflies and do not migrate; instead, the species inhabits sites year-round (as egg, larva, pupa and adult), typically moving within only a few hundred yards of their natal locations. Adults emerge from their chrysalids (pupae) during species-specific time periods; the golden hairstreak’s adult period is August through September. 

The golden hairstreak’s primary nectar plants are late-summer flowers in tree canopy and herbaceous forest edge. Both males and females feed by using their long proboscis to sip floral nectar. Males of most species require salts, which they obtain from evaporated puddles and moist soil and animal urine and feces. 

Males begin emergence first, followed by females; late season individuals are primarily or solely females. Weather influences butterfly emergence and the flight period duration, with wet or cold conditions potentially delaying emergence, and warm, dry conditions promoting earlier emergence. 

Male lycaenids seek mates using patrolling patterned flight or perching on vegetation in select spots and darting out to inspect passing butterflies. Females search for egg-laying sites by slowly flying and hovering above hostplant vegetation, and then landing and crawling to inspect vegetation before depositing eggs singly.

Larvae are slug-like in appearance and highly camouflaged in their host species. Many lycaenid larvae engage in mutualistic relationships with ants, known as myrmecophily, which typically consists of ants tending and milking larvae, obtaining nutrition in the form of a nectar-like substance (honeydew) in the process, and also protecting larvae from predators and parasitoids; in some situations the ants move butterfly larvae or pupae into ground chambers, including their nests. Ant interactions have been observed with golden hairstreak; however, more study is needed to determine the extent of interaction and ecological significance of ant-larval relationships. The overwintering stage varies by lycaenid species: golden hairstreak overwinter as eggs.

Geographic range

The distribution of this species is limited in part by a combination of its dependence on rare hostplant occurrence within rare habitat types. Its distribution and abundance in Washington is characterized by small numbers of small isolated populations. The species' overall range is disjunct and limited by its golden chinquapin host in northern Oregon Cascades Range, a small area in the Oregon Coast Range and a small area in the southern Washington Cascades; occurrence in Washington has been documented in Skamania County. 

For a map of range-wide conservation status and distribution, check out NatureServe Explorer.