Brephidium exilis

This species’ shadow is often noticed before the actual individual. They are one of North America’s smallest butterflies.
Photo Credit: stonebird @ Encyclopedia of Life
Brephidium exilis
Common Name: western pygmy-blue
Animal Guild: Insect
Class > Order > Family: Insecta > Lepidoptera > Lycaenidae
What does the species look like?

This species is tiny. The upperside of their wings is copper-brown with dull blue at the bases of both wings. The underside of the hindwings is copper-brown with a mostly white fringe and three small black spots near the base, and a row of black spots at the outer margin.

Caterpillars are green.

Total adult length: 0.5 to 0.6 inches (12.7 - 15.2 mm).

Similar species: Western Pygmy-blue butterflies may be confused with the slightly larger species, Marine Blues (Leptotes marina) or Reakirt’s Blues (Hemiargus isola). Marine blues have a lot more stripe and more busily-patterned underwings. Reakirt’s blue is much darker blue in coloration overall.
Where is the species found?
States & Provinces
AL, AR, AZ, CA, CO, FL, GA, ID, KS, MS, NM, NV, OK, OR, SC, TX, UT
Distribution

This species occurs across the western half of the United States. The eastern Pygmy-blue occurs across the southeastern United States. Although distribution information is lacking.

The Western Pygmy-blue butterfly is most commonly found in lowlands, disturbed areas or dry benches above watercourses throughout the desert southwest. Despite its small size this species can travel great distances.
General Phenology and Life History

 Year-round in the deserts, only warm seasons elsewhere.
Which phenophases should I observe?
Do you see/hear...?
Activity Adults
One or more adults are seen or heard moving about or at rest.
More...

For abundance, enter the number of individual animals observed in this phenophase.
Adults feeding
One or more adults are seen feeding with their straw-like tongue (proboscis). If possible, record the substance and species on which they are feeding (for example, nectar, sap, dung, or moist soil) in the comments field. For Brephidium exilis, adults feed on the flower nectar of many different plant species.

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Flower visitation
One or more individuals are seen visiting flowers or flying from flower to flower. If possible, record the name of the plant or describe it in the comments field.

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Reproduction Mating
A male and female are seen coupled in a mating position, usually end to end. This can occur at rest or in flight.

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Egg laying
A female is seen laying eggs on a plant or other surface. If possible, record the name of the plant or describe it in the comments field. For Brephidium exilis, eggs may be deposited on many different plants species, often on plants in the goosefoot family (Chenopodiaceae).

For abundance, enter the number of individual animals observed in this phenophase.
Eggs
One or more eggs are seen on a plant or other surface. If possible, record the name of the plant or describe it in the comments field. For Brephidium exilis, the tiny, pincushion-shaped, pale green eggs may be found on many different plants species, often on plants in the goosefoot family (Chenopodiaceae).

For abundance, enter the number of individual animals observed in this phenophase.
Development Caterpillars
One or more caterpillars (larvae) are seen moving about or at rest. When seen on a plant, if possible, record the name of the plant or describe it in the comments field. For Brephidium exilis, caterpillars have a wide, rough-textured body and are green in color, sometimes developing brown and cream-colored chevron markings down their back depending on the plants they are eating.

For abundance, enter the number of individual animals observed in this phenophase.
Caterpillars feeding
One or more caterpillars are seen feeding. If possible, record the name of the species or substance being eaten or describe it in the comments field. For Brephidium exilis, caterpillars feed on many different plant species, often on plants in the goosefoot family (Chenopodiaceae).

For abundance, enter the number of individual animals observed in this phenophase.
Pupae
One or more pupae are seen in a cocoon or shell (puparium). For Brephidium exilis, pupae are enclosed in a smooth, ovoid, pale green, translucent shell (chrysalis) that appears darker as the butterfly develops, and are typically found on or near a host plant in the goosefoot family (Chenopodiaceae). Do not include empty pupal shells after the adult has emerged from them.

For abundance, enter the number of individual animals observed in this phenophase.
Dead adults
One or more dead adults are seen.

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Dead caterpillars
One or more dead caterpillars are seen.

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Method Individuals at a feeding station
One or more individuals are seen visiting a feeder, feeding station, or food placed by a person.

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Individuals in a net
One or more individuals are seen caught in a net.

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Individuals in a trap
One or more individuals are seen caught in a trap.

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What do these phenophases look like?

There is currently no photoguide available for this species. If you'd like help us create one, use the guidance document and species template provided here. Then send it via email to education@usanpn.org when it is complete.