Silvery Blue

S2

Silvery Blue

Scientific Name

(Glaucopsyche lygdamus)

The Silvery Blue is a small butterfly in the Lycaenidae family (1). They have one generation per year and adults can be seen flying from mid-April to early-May (1, 2). In the U.S. you can find this butterfly from coast to coast, as well as Canada and Alaska (3). In Maryland, this species is reported in Garrett, Allegany, and Washington Counties (4), and it has a state rank of S2 (2).

Photo by Justin MeissenLicensed under: cc-by-sa-2.0

Photo by Jared Satchell Retrieved from Maryland Biodiversity Project

Identification

The Silvery Blue is a small butterfly with a wingspan of 7/8-1 1/4 inches (5). Males have more vibrant uppersides with a bright blue while females are more silvery (3). Their underside is a brownish grey with large uniform round black spots along their postmedian (3, 5). Males also have a thin black border on the edge of their wings, while females have a wider border. Both sexes have a white fringe (6).

Photo by Brad SmithLicensed under: CC BY-NC 2.0

Life Cycle

Adults fly from mid-April to early-May, and frequently visit Eastern Redbud (Cercis canadensis), Common Cinquefoil (Potentilla simplex), and composites sites (2). Males patrol the host plant awaiting females.

Females lay eggs singly on host flower buds and occasionally on young leaves (3). Their larval host plants are in the Leguminosae family, specifically the Carolina Vetch (Vicia caroliniana), which can be found in western Maryland (3, 4).

Larvae spend their days eating the flowers, fruit, and leaves while also being tended to by ants (3). In exchange for protection, the larva will secrete sugar filled nectar from a gland called the nectar organ (7).

Photo by Alan SchmiererLicensed under: CC-Zero

Silvery Blue being tended to by antsPhoto by Atticus MurphyRetrieved from Tufts Pollinator Initiative

Photo by Atticus MurphyRetrieved from Tufts Pollinator Initiative

Larvae vary in appearance; they may be pale green, pale brown, purplish, or a grayish-green with purple on the end of their abdomen. Most often, they will have a dark green, red, or reddish-brown dorsal band that is lined with white or yellowish color (3). Their pupa is either brown with a dark middorsal line and multiple light brown markings or black with no markings. They hibernate as a pupa (3).

Habitat

In Maryland, this butterfly enjoys open fields alongside woodlands and dry slopes among shale barrens (2, 4). In other regions they can be found near streams, meadows, coastal dunes, and even on the edge of the artic/alpine tundra (3, 5).

Larval Host Plant: Carolina Vetch

Photo by Joshua MayerLicensed under: cc-by-sa-2.0

Adult Host Plants

Photo by Bill HubickRetrieved from Maryland Biodiversity Project

Eastern Redbud

Photo by Fritzflohrreynolds. Retrieved from wiki imagesLicensed under: CC-BY-SA-3.0

Common Cinquefoil

Distribution in Maryland

Data from Maryland Biodiversity Project. Includes historical records and may overrepresent the current range of the species.

How can you help?

In order to help this species, we need to maintain natural open fields with nearby woodlands. Preservation of natural habitats is most beneficial.

References

Forister, M. L., J. A. Fordyce, A. C. McCall, and A. M. Shapiro. 2011. A complete record from colonization to extinction reveals density dependence and the importance of winter conditions for a population of the silvery blue, Glaucopsyche lygdamus. Journal of Insect Science 11(130): 1-9.
Davis, L. and R. Smith. 2014. Butterflies of Maryland: A biological checklist. Maryland Department of Natural Resources, Wildlife and Heritage Division. https://dnr.maryland.gov/wildlife/Documents/butterfliesofmaryland_biological-summary_checklist.pdf
Scott, J. A. 1977. The butterflies of North America: A natural history and field guide. Stanford University Press. pp. 399-400.
Maryland Biodiversity Project. Silvery Blue Glaucopsyche lygdamus (Doubleday, 1841) https://www.marylandbiodiversity.com/view/539. Last accessed 20 September 2020.
Opler, P. A. 1994. Peterson first guide to butterflies and moths. Houghton Mifflin Company. New York, pp. 44-45.
Butterflies and Moths of North America. Silvery Blue Glaucopsyche lygdamus (Doubleday, 1841) https://www.butterfliesandmoths.org/species/Glaucopsyche-lygdamus. Last accessed 20 September 2020.
Tufts Pollinator Initiative. 2019. The butterflies who are raised by ants https://sites.tufts.edu/pollinators/2019/07/the-butterflies-who-are-raised-by-ants/. Last accessed 26 September 2020.

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