Callophrys gryneus

Distinguished from the similar Callophrys hesseli (Hessel's hairstreak) by: more blue-green color in Hessel's, postmedian line edged with brown on both sides (not just inward), and presence of white spot near forewing costa in Hessel's. Distinguished from Callophrys xami by lacking the sharp W mark in the postmedian white band that characterizes C. xami. Subspecies identification requires attention to presence/absence of postbasal spots, shape of postmedian line (zigzag vs. straight), and extent of brown vs. green on underside.

Bluffs, open fields, barrens, and dry or rocky open places. Almost always found near or on junipers (Juniperus) or related conifers in these habitats.

North America. Records from Vermont and across the United States; distribution varies by subspecies with different host plant associations in eastern and western populations.

Varies by subspecies and region. The gryneus and sweadneri races have two broods per year; siva has two or three broods; nelsoni, muiri, and thornei have one brood; loki has one or two broods. Adults active spring through summer depending on location and brood number.

Adults visit flowers for nectar, especially near host plants. Both sexes observed visiting flowers, with sweadneri race noted as particularly avid flower visitors.

• Juniperus virginiana - host plantEastern redcedar; used by gryneus and sweadneri races
• Juniperus ashei - host plantAshe juniper; used by gryneus race
• Juniperus communis - host plantCommon juniper; used by siva race
• Juniperus deppeana - host plantAlligator juniper; used by siva race
• Juniperus osteosperma - host plantUtah juniper; used by siva race
• Juniperus scopulorum - host plantRocky Mountain juniper; used by siva race
• Juniperus californica - host plantCalifornia juniper; used by siva and loki races
• Calocedrus decurrens - host plantCalifornia incense-cedar; used by nelsoni race
• Thuja plicata - host plantWestern red-cedar; used by nelsoni race
• Cupressus sargentii - host plantSargent's cypress; used by muiri race
• Cupressus forbesii - host plantTecate cypress; used by thornei race

Females lay eggs singly at the tip of host plant leaves. Eggs pale green with white ridges. Larvae vivid green with faint middorsal stripe, whitish-yellow spots on either side of stripe, and whitish-yellow subspiracular stripe. Chrysalis brown to pale brown (gryneus race) or dark brown (western races), mottled with black, abdomen somewhat reddish in gryneus race. Overwinters as chrysalis.

Males highly territorial on cedar trees, perching in search of females. Males can be flushed by gently shaking host trees. Both sexes visit flowers for nectar.

Herbivore on junipers and related conifers. Adult pollination of flowers. Larval stage consumes foliage of host conifers.

Subject of taxonomic research regarding species boundaries. Observed by butterfly enthusiasts and citizen scientists. Some subspecies with restricted host plant ranges may be of conservation interest.

• Callophrys hesseliOnly similar species in range; distinguished by blue-green color, postmedian line edged brown on both sides, and white spot near forewing costa
• Callophrys xamiRelated North American hairstreak; distinguished by sharp W mark in postmedian white band on wings, which C. gryneus lacks

• butterfly
• hairstreak
• lycaenid
• North America
• juniper
• conifer specialist
• territorial males

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Bug Eric: City Nature Challenge 2023 Recap
• Psychidae | Beetles In The Bush
• Performance of DNA barcodes for informing the subspecies controversy in North American populations of Callophrys gryneus (Hübner, [1819]) (Lepidoptera: Lycaenidae)