Glaucopsyche lygdamus “Silvery Blue” Lycaenidae

Glacier National Park, MT
June 21, 2014
Robert Niese

As with many members of the Lycaenidae family (blues, coppers, and hairstreaks), the caterpillars of this species are tended by ants which provide the vulnerable larvae with protection in exchange for sugary “honeydew” which the caterpillars excrete from their backs. Check it out.