Our species profile for this issue is tl1e Golden Hairstreak, Habrodais grunus. The Golden Hairstreak belongs to the family Lycaenidae, the large worldwide family of butterflies which includes all blues, coppers, hairstreaks and metalmarks. Lycaenids are typically small, nectar­ feeding species. The Golden Hairstreak is unique among Washington’s Lycaenids in several respects. It flies very late in the season; it is said to be crepuscular, flying at twilight and early morning, and often in shade; and its larva feeds on a plant used by no other Washington butterfly. It is also somewhat larger than most other Lycaenids, and it is the only American butterfly placed in the genus Harbrodais.

Why all these unique features? Because the Golden Hairstreak is an outlier, a far north extension of a group of butterflies with tropical affinities. It really has no close relatives in this region.

The Golden Hairstreak flies only where its food plant, the Chinquapin tree, occurs in Washington. The range of this tree is severely restricted in Washington occurring only in two tiny areas, one in Skamania County near the Columbia River Gorge, and the other along western Hood Canal. The hairstreak is known only from the Skamania County site. Further south in Oregon and California the Golden Hairstreak also feeds on several species of oak and is more widely distributed. As Garry Oak is not among the species’ foodplants, the Golden Hairstreak has not expanded into the oak groves of Washington.

Because of its food plant restrictions, the Golden Hairstreak is one of Washington’s rarest butterflies. It is found flying late in the season, long after most other hairstreaks have completed the adult portion of their life cycles, and only in the immediate vicinity of Chinquapin trees in a tiny area of Skamania County near Willard. Thanks to the efforts of Robert Michael Pyle and others, the Forest Se1vice has inventoried and is now protecting the few remaining Chinquapins rather than eradicating them as junk trees as previously planned.

The Golden Hairstreak is well named, as the egg, larva, chrysalis and adult are all pale yellow to golden in color, closely matching the color of the underside of the Chinquapin leaf. Like all six of our hairstreak species of the genus Satyrium, the Golden Hairstreak overwinters in the egg stage. The egg is placed on the underside of the Chinquapin leaf very close to the edge and often near the stem. A tiny black wasp is known to parasitize some of the overwintering eggs; parasitized eggs appear to hatch several weeks later than healthy eggs, with winged wasps emerging directly from them.

Our tiny database of Washington information indicates that the healthy egg hatches in mid June and the yellow larva “feeds up” quickly on tender new terminal Chinquapin leaves, quickly pupating to a golden ch1ysalis anchored by a silk cremaster at one end and a silk girdle strand in the middle. It appears, again based on ve1y limited information, that the butterfly may remain in chrysalis for quite a long time, perhaps a month, before emerging as an adult butterfly in mid August. Unconfirmed and tentative reports of Golden Hairstreak sightings as early as June warrant further investigation however.

The Golden Hairstreak adult should not be confused with any other Washington butterfly. Its relatively large size, golden color both dorsally and ventrally, and hairstreak “tails” render it unique in appearance. Fresh adults also have subtle reddish-orange markings on the ventral wing surfaces, forming two parallel broken lines of dashes across the middle and

All Photos by Dave Nunnallee

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