Marine blue
This small butterfly breeds year round across the warm southwest and each summer strays north as far as the north-central plains and southern Oregon.
| Where | Gardens, scrublands and alfalfa fields |
|---|---|
| Size | 22 to 29 mm wingspan |
| When | March to November |
Males of the Marine blue show a light violet-brown sheen above, while females are duller brown with some blue at the wing bases; both sexes have undersides crossed by soft gray-brown bands edged in white.
Caterpillars feed on a range of legumes, including alfalfa, milk vetch, clover and the ornamental plumbago, and the species produces several overlapping generations each year wherever its host plants keep growing.
Traits
Habitat
Garden
Colour
Brown, Blue, Grey
Active
Day
To people
Harmless to people; adults visit garden flowers for nectar and rarely settle for long.
Activity through the year
Often confused with
Reakirt's blue shows a row of black, white-ringed spots across the underside forewing, while the Marine blue's underside instead has plain gray-brown bands without that spotted row.
Questions
Is the Marine blue dangerous to people?
Harmless to people; adults visit garden flowers for nectar and rarely settle for long.
When can you see the Marine blue?
The Marine blue can be seen from March to November, by day.
Plate retouched from a photo by Tom and T Herman, CC BY 4.0, iNaturalist Licence
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Butterflies and moths›Blues and coppers›Leptotes
Last updated 2026-09-27. Every entry is checked against published sources.