Long-tailed Pea Blue (Lampides boeticus) — identification, habitat & look-alikes

The long-tailed pea blue is a small butterfly with a thread-like tail on each hindwing and a finely waved, tan-and-white underside. In the US it lives only in Hawaii, where it was introduced, and it isn't found on the mainland. Its caterpillars feed inside the flowers and pods of peas, beans, and other legumes. It's also simply called the pea blue or long-tailed blue.

Appearance

Appearance: Wingspan is about 1–1.3 in (24–34 mm). Males are mostly violet-blue above with brown edges, while females are brown with only a little blue near the center. Underneath, both sexes are tan with wavy white lines, and two black spots sit beside the tail.

Look-alikes

Hawaiian blue (koa butterfly)Udara blackburni

The Hawaiian blue's underside is plain green, so it looks green when perched with its wings closed. The pea blue's underside is tan with wavy white lines, with a thin tail and two black spots on each hindwing.

Why they get mixed upBoth are small blue butterflies in Hawaii, and the Hawaiian blue is one of only two native butterflies there.

Where it lives

Typical habitats: Gardens and bean fields
Flowery open areas
Forest edges
Range: Native to warm parts of Europe, Africa, southern and Southeast Asia, and Australia. In the US it occurs only in the Hawaiian Islands.
Preferred conditions: Favors hot, flowery places and has been found up to about 8,900 ft (2,700 m).
Migration: A strong flier and well-known migrant that can travel long distances.

Life cycle

Larva: Females lay single eggs on flower buds. The caterpillars are green or reddish-brown with a dark stripe down the back and reach about 0.6 in (15 mm).
Caterpillar food plants: Caterpillars eat the flowers, seeds, and pods of many plants in the pea family, including garden peas and beans.