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Palos Verdes Blue Butterfly

Palos Verdes Blue Butterfly

The Palos Verdes Blue (Glaucopsyche lygdamus palosverdesensis) is a small endangered butterfly native to the Palos Verdes Peninsula. With its distribution limited to one single site, the southern slope of the Palos Verdes Peninsula, it has one of the best claims to being the world’s rarest butterfly.

Astragalus trichopodus
Astragalus trichopodus

It is a localized subspecies of the Silvery Blue (G. lygdamus) and is distinguished from other subspecies by its slightly different spot patterning on the underside of the wing, an earlier flight period, and use of locoweed (Astragalus trichopodus) as a larval food plant. There are currently 11 subspecies of silvery blue. The Palos Verdes Blue subspecies was first 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.

The Palos Verdes blue butterfly was thought to be driven to extinction in 1983 by development of its habitat, but 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.

Lotus scoparius - common deerweed
Lotus scoparius – common deerweed

How can you help?

Plant butterfly-friendly gardens. The Palos Verdes Blue persists in a coastal sage scrub habitat. This species is locally monophagous, or particular to one species of food plant. The entire species was originally thought to be particular only to the locoweed (Astragalus trichopodus lonchus), but the population rediscovered in 1994 used common deerwood (Lotus scoparius) as its larval food plant.

These two types of plants are fast becoming scarce on the Palos Verdes peninsula because of housing development. Retention of these larval food plants is essential for conservation of the Palos Verdes Blue. Plant some in your garden today!

The Palos Verdes Peninsula Land Conservancy (PVPLC) hosts a Native Plant Sale every 4th Saturday at White Point Nature Education Center & Preserve. Purchase drought-resistant native plants grown in the Conservancy’s own nursery!

Find other places to purchase or view native plants here, courtesy of the PVPLC.

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