New Jersey Butterfly Club

Acadian Hairstreak

Satyrium acadica

Identification: Very small—size of thumbnail, but just a bit larger than most of NJ's other Satyrium hairstreaks. Almost never seen with wings open. Below: FW and HW light gray, each with a band of small, white-ringed dark spots. Single blue spot within orange band on hindwing has obvious orange cap.

NJ Status and Distribution: Former resident. The last known NJ location was a fen along the Appalachian Trail in Sussex County where one was seen in 2012. Has not been reported from two other Sussex County wetlands since 2005. Formerly more widely distributed in the northern counties. Has also apparently disappeared from several locations in nearby Orange County, NY, and in Massachusetts.

Habitat: Wetlands with shrub willows.

Flight Period: One brood that may fly from mid-June to late July. Extreme dates: 6/29—7/12 (these dates are more restricted because of few records).

Caterpillar Food Plants: Shrub willows (Salix).

Overwintering Stage: Egg.

Good Locations: None.

Comments: Wetlands with shrub willows are not uncommon in north Jersey. Acadian Hairstreak may be dependent on some species of ant (perhaps in the genus Formica) to transport and protect (farm) the larvae. This species may also be another victim of our warming climate.