Plebejus melissa Melissa Blue

Initially I found Plebejus melissa nectaring on a notoriously distinct genus – Asclepius. There are many, many features of the blossoms in this group of plants that make it easy to identify. Supportive images of the plant could not be found in a general search, however. There are 223 species of Asclepius world-wide of which 91 are native in the U.S. A search through the 91 files of native Asclepius on the USDA site proved unproductive in my quest to identify the plant. Concentrating on the range of the Plebejus melissa – and then looking through county records – exposed leads that ultimately proved helpful.

Plebejus melissa adults will feed on:
Agoseris heterophylla
Asclepias hallii
Leucanthemum vulgare
Matricaria recutita
Potentilla
Rudbeckia hirta
Taraxacum officinale
Trifolium repens

All but the Agoseris and the Taraxacum are in cultivation.

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More information can be found at Butterfly & Moths, and Butterflies of America. The Natural History Museum does not have host plant data for Plebejus melissa.

I found the America site particularly helpful in a quest to sort out the distinction between this butterfly and a close relative, the endangered Karner Blue. The Melissa Blue has a more conspicuous band of orange dots going up the wings on the underside. The ‘blue’ side of these blues have distinct markings as well. The range of the two butterflies is pried apart – the Karner resides in the north east while the Melissa is further west. As for the formal names of these two closely related species, I settled on the convention used by Butterflies of America to assign a distinct specie name of Plebejus samuelis to the Karner Blue.
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Dandelion and the top view of a female Melissa Blue are shown here in Creative Commons images, along with a Rudbeckia hirta photo by Susan Dunlap. The Melissa Blue male lacks the yellow-framed spots.