Glaucopsyche piasus gabrielina

San Gabriel Mountains Arrowhead Blue

I visited the type locality a few times years ago, and found this blue flying in good numbers on June 13th, 2008. The location is at Mt. Islip in the San Gabriel Mountains, at 7600-8000' elevation, specifically a ridge running east from there. The lupine there is Lupinus elatus. John Emmel collected the types in 1974 on June 22nd, and it seems that the time to look for this population is from early June to early July. Dr. Emmel told me the various populations in southern California tend to have minor differences and don't sort themselves out neatly. For instance, he considered the population near Mt. San Gorgonio that uses L. andersonii "near gabrielina for want of a better label". This butterfly is lighter ventrally than sagittigera, with less well-defined "arrowhead" markings; it also flies one to three months later and uses a different lupine host.

San Gabriel Mountains Arrowhead Blue - Glaucopsyche piasus gabrielina
Glaucopsyche piasus gabrielina - the 'San Gabriel Mountains' arrowhead blue - at Mt Islip, the Type Locality, on June 13, 2008. John Emmel, who collected the types and co-described this subspecies, told me this photo "really captures the typical phenotype of this subspecies."
San Gabriel Mountains Arrowhead Blue - Glaucopsyche piasus gabrielina
Another view of gabrielina on host Lupinus elatus at Mt Islip on June 13, 2008.
San Gabriel Mountains Arrowhead Blue - Glaucopsyche piasus gabrielina
Male dorsal gabrielina at Mt Islip. Subspecies gabrielina flies early June to early July, often with fellow lupine-user Boisduval's blue. June 13, 2008.

©Dennis Walker