Learn more about the Marine Blue Butterfly

Marine blue butterfly, also known as marine Striped blue, is a butterfly that lives in South, North, and Central America and is unique for its lack of a tail and soft blue color.

Marine Blue Butterfly Species Summary

Scientific NameLeptotes marina
Family NameLycaenidae
HabitatSouthwestern deserts, subtropical lowlands, coniferous forests, and open weedy areas
RangeCalifornia, New Mexico, Indiana, Wisconsin, Arizona, Kentucky
Host PlantsLeadwort, alfalfa, California false indigo, mesquite
Butterfly DescriptionBlue upperside with faint veins and patterns
Caterpillar DescriptionPale green, camouflages with the host plants

Butterfly Physical Description

marine blue butterfly
Marine blue butterfly

Marine blue (scientific name Leptotes marina, family Lycaenidae, subfamily Polyommatinae) is a tiny butterfly with a wingspan of 0.87 inches to 1.14 inches (2.2 to 2.9 cm). Its upper side is gentle blue with a whitish edge on the forewings and hindwings. This butterfly also has slightly noticeable veins on its wings.

The male upper wing is pale brown with white markings. The female’s upper wing is purple-blue. The underwings are tiger-striped with tan and white bands and two dark spots on the lower end.

Comparison with other species

This butterfly shares some similarities with Common blue and Holly blue butterflies. All three have a faint blue color on the top side of their wings, with Marine blue having more prominent veins and patterns than others. It also has a slightly different wing shape, and its body is not as fluffy.

Caterpillar Physical Description

The Marine blue butterfly caterpillar changes colors with every instar. At first instar, the caterpillars have a pale green color which can change to red and green stripes to blend with the plants they’re eating. Still, the larvae do not build nests and do not feed on leaves. They feed on developing flowers, flower buds, seeds, and flower petals, although rarely.

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Marine blues are common in Southern California, New Mexico, Indiana, and the following areas:

  • Indiana
  • Wisconsin
  • Louisiana
  • Colorado
  • Kentucky
  • Arizona
  • Montana
  • Texas
  • Utah


Leptotes marina is ecologically flexible and is commonly found in southwestern deserts, subtropical lowlands, coniferous forests, and open weedy areas, including:

  • City gardens
  • Mesquite scrub
  • Alfalfa fields
  • Waste areas

Host Plants

The Marine blue larval food plants include leadwort (Plumbago), alfalfa (Medicago sativa), milkvetch (Astragalus), mesquite (Prosopis), as well as:

  • California false indigo (Amorpha californica)
  • Wait-a-minute bush (Acacia greggii/Senegalia greggii)
  • Purple prairie clover (Dalea purpurea)
  • Hyacinth bean (Dolichos lablab)
  • Wild licorice (Glycyrrhiza lepidota)
  • Desert fern (Lysiloma thornberi)
  • Sweet pea (Lathyrus odoratus)
  • Wild bean (Phaseolus)
  • Chinese wisteria (Wisteria sinensis)


The Marine blue larvae’ food source is seeds, developing flowers, and flower buds of leadworts and plants in the legume family.

Adult Marine blues get nectar from:

  • Dogbane
  • Rabbitbrush
  • Wild buckwheat
  • Cirsium
  • Sweet clovers
  • Geranium
  • Knotweed
  • Schinus

Adult Striped blues have also been reported to source other nutrients from damp soil and dung.

Behavior and lifespan

marine blue butterfly
Marine blue butterfly

Marine blues males patrol near host plants by flashing on wings and “calling” on females using pheromones. After mating, the females lay eggs singly on the flower buds. The egg stage lasts 3 to 6 days.

The caterpillars are myrmecophiles, which means they form a close association with ants. The ants protect the caterpillars from parasitoids. The caterpillars have a gland that secretes honeydew. Ants are attracted to this honeydew and protect the caterpillars in exchange for food.

After 2 to 3 weeks, the caterpillar will form a chrysalis (pupa). Pupation often occurs on leaf litter under the host plants. Adult butterflies emerge after 8 to 12 days. The adults’ lifespan is 4 to 10 days.

The flight season of this species is from April to September in the North and through the year in Southern California and South Texas.


The predators of the Marine blue butterflies are similar to those of other butterflies. These predators include:

  • Birds
  • Lizards
  • Spiders
  • Rodents
  • Wasps

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