Palos Verdes Blue - Overview

Overview

Palos Verdes Blue (G. lygdamus palosverdesensis) is a localized subspecies of the Silvery Blue (G. lygdamus). It was described in 1977, shortly before it became one of the second groups of butterflies to be listed under the US Endangered Species Act in 1980. It is distinguished from other subspecies of G. lygdamus by its slightly different patterning on the underside of the wing, an earlier flight period, and use of a locoweed (Astragalus trichopodus) as a larval food plant. The distribution of the subspecies as described was the southern slope of the Palos Verdes Peninsula in coastal Los Angeles County.

The Palos Verdes blue butterfly was thought to be driven to extinction in 1983 by development of its habitat. Then, in 1994, the butterfly was rediscovered by Rick Rogers, Rudi Mattoni, and Timothy Dahlum at the Defense Fuel Support Point in San Pedro, which is located on the northern (inland) side of the Palos Verdes Peninsula. This new population lays eggs on an additional foodplant (common deerweed, Lotus scoparius) but shares physical and behavioral characteristics with the other now-extinct populations.