Alternate Common Names:Orange-Bordered Blue, Karner Blue.
Note: This species is referred to with the genus name Plebejus by some authors.
This species ranges from central Canada, south through most of the western half of the U.S., and east through the Great Lakes states to New Hampshire. It occurs throughout Idaho.
In the west it occurs in open areas such as meadows and prairies; in the east, it occurs in sandy habitats.
Caterpillars feed on the new leaves and flowers of a variety of legumes, including
lupines (Lupinus spp.), alfalfa (Medicago spp.), and milkvetch
Adult: Butterflies drink flower nectar.
The caterpillar is equipped with a honey gland, also known as a dorsal nectary organ, which emits a sugary solution agreeable to ants. The ants feed on the solution and in turn protect the caterpillar from predators. Also for protection, the caterpillar bears a pair of everscible tubercles or tentacles on the eighth segment. These tubercles are usually housed within the body, but when the caterpillar feels threatened by the approach of a potential predator, they can be pushed out to release a chemical which mimics an ant alarm pheromone. This scent causes the ants to become frenzied and aggressive, and the potential predator takes leave or is eaten by the ants. There are two generations of caterpillars each summer in the east, and three in the west. Each caterpillar undergoes four stages of growth, called instars. Either the egg overwinters, or the newly hatched caterpillar overwinters in a physiological state called diapause. Adults generally fly from April to November.
Males actively patrol in search of receptive females. Females lay eggs by walking down the stem of a host plant, ovipositing along the way and at the base of the plant. The eggs are green with white ridges.
|Idaho Status:||Unprotected nongame species.|
|Global Rank:||G5; most populations are widespread, abundant, and secure. One subspecies in New York, the Karner Blue (L. melissa samuelis), is ranked as T2, imperiled and vulnerable to extinction, and is protected.|
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