Medium-sized butterfly with a wingspan up to 2-1/2 inches. The upperside is bright yellow, but some summer form females may be orange-yellow or off-white. The male has few or no markings; the female has a band of narrow dark spots along the upper wing margins and a cell-shaped spot on the forewing. The underside of both is greenish-yellow; the female has pinkish-bordered, silvery cell spots on both wings. Winter form males are larger and have darker markings on the underside. The color of the caterpillar varies but usually is green with a yellow stripe and blue patches on the side that contain many small, dark spines arranged in transverse bands. The head is green, with raised black spots. Caterpillars that eat mostly flowers turn yellow, with dark bands. The pupa is compressed from side to side and is green or pink with yellow lines.
Southern United States west to California; strays north to New Jersey and Canada; West Indies, Mexico, Central America and South America; not cold-hardy.
Distribution and Abundance in Florida:
Common and widespread all year in Florida; adults and caterpillars present most of year. Millions of adults migrate south to Central Florida in the fall. Adults that overwinter in reproductive diapause migrate north in the spring.
Wide range of habitats, including forests and open, disturbed sites.
Three or more broods per year; breeds mostly in disturbed areas. The spindle-shaped eggs are laid singly on the young leaves or flower buds of the host plants; they are white when laid but turn orange over time.
Adults fly high in one direction with deep wing beats. Eggs and young caterpillars may be eaten by ants that are attracted by nectar glands on the host plants.
Caterpillars feed on the leaves and flowers of the host plants. Native larval host plants include sicklepod (Senna obtusifolia), the cultivated shrubs Bahama senna (Senna mexicana var. chapmanii) and privet senna (Senna ligustrina) and the cultivated wildflowers Deering partridge pea (Chamaecrista deeringiana) and partridge pea (Chamaecrista fasciculata). Other native larval host plants include the weedy hairy sensitive pea (Chamaecrista nictitans var. aspera) and the critically imperiled sensitive pea (Chamaecrista nictitans var. nictitans). The larvae also feed on nonnative trees and shrubs, including candlestick plant (Senna alata) and glossy shower (Senna surattensis) and the nonnative, weedy large herb coffee senna (Senna occidentalis). Small larvae eat holes in the leaves; larger ones eat leaves from the edge. Adults typically nectar on red flowers; they have relatively long tongues and can feed on tubular flowers such as the native scarlet creeper (Ipomoea hederifolia) and tropical sage (Salvia coccinea) and the nonnative cypressvine (Ipomoea quamoclit).