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Insects and other arthropods

Silvery blue

Glaucopsyche lygdamus

Tabs group


It’s easy to see where this small butterfly gets its name: its wings are blue on top and silvery beneath. The top of the wing in the males is an iridescent blue, with a narrow dark border. In the females the blue is darker and the border is wider. Both sexes have a white fringe around the wings, and a row of white-ringed black spots on top. Their wingspan is 3.2 cm.

Life cycle

Like all butterflies, the silvery blue goes through four stages: egg, caterpillar, chrysalis and adult. There is just one generation per year, and the insect overwinters as a chrysalis. In the spring, once the metamorphosis is complete, the adults seek a partner. The fertilized females lay their eggs singly on the floral buds and young leaves of their host plants. The caterpillars, often accompanied by ants, spend their time feeding on the plants. They moult several times over the course of the summer and finally pupate.

Geographic distribution

In North America, this species is found from Alaska all the way south to Baja California, in the west, and across the continent as far east as Nova Scotia.

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