It seems reasonable to think that this species of Blue would be associated with lupines, but the name is a misnomer. The larvae instead feed on leaves, flowers, and fruits of several species of perennial wild buckwheats (Eriogonum, family Polygonaceae). According to Art Shapiro, a professor of evolution and at UC Davis, “under the International Code of Zoological Nomenclature, there’s nothing one can do about that!” This small butterfly ranges throughout the western US and southwestern Canada in mid-elevation meadows, rocky outcrops, chaparral, and sagebrush. There are several flights throughout most of their range, but only one in the Sierra Nevada.
Photo by Glenn Marangelo on 7/3/20 near Potomac, MT.