Alternate Common Names:Emerald-Studded Blue, Silver-Studded Blue.
Note: The distinctions between this species and the Lupine Blue, Plebejus [Icaricia] lupinus, are unclear and debated by scientists.
A widespread species, it ranges from southern British Columbia east to southwestern Saskatchewan, and south through the western half of the U.S. to Mexico. It occurs throughout Idaho. Isolated populations may occur in Minnesota and New Jersey.
It utilizes a wide variety of habitats, including fields, prairies, open woodlands, and deserts.
Caterpillars feed on the leaves, flowers, and fruits of wild buckwheat (Eriogonum
spp.) and legumes such as trefoils (Lotus
spp.), milkvetches (Astragalus spp.), and lupines (Lupinus spp.).
Adult: Butterflies drink flower nectar.
Caterpillars often can be found inside host plant pods. Each 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 can be several generations of caterpillars each summer in most of the range, but only one in the north. Each caterpillar undergoes four stages of growth, or instars. Young caterpillars overwinter in a physiological state called diapause. Adults generally fly from February to october. Butterflies may disperse to some degree, as the isolated populations in Minnesota demonstrate. The New Jersey population was probably introduced. This is one of the most common Blues in the west.
Males actively patrol in search of receptive females. Females lay light green eggs singly on the leaves and flowers of host plants.
|Idaho Status:||Unprotected nongame species.|
|Global Rank:||G5; populations are widespread, abundant, and secure.|
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