The Heliconiinae, commonly called heliconians or longwings, are a subfamily of the brush-footed butterflies (family Nymphalidae). They can be divided into 45–50 genera and were sometimes treated as a separate family Heliconiidae within the Papilionoidea. The coloration is predominantly reddish and black, and though of varying wing shape, the forewings are always elongated tipwards, hence the common name.
Most longwings are found in the Tropics, particularly in South America; only the Argynnini are quite diverse in the Holarctic. Especially tropical species feed on poisonous plants, characteristically Passifloraceae vines, as larvae, becoming poisonous themselves. The adult butterflies announce their acquired toxicity with strong aposematic colors, warning off would-be predators. There are several famous cases of Batesian and Müllerian mimicry both within this group and with other butterflies. Other commonly seen foodplants are Fabaceae (which also contain several toxic species), and particularly among northernly species Violaceae.
A butterfly is a mainly day-flying insect of the order Lepidoptera, which includes the butterflies and moths. Like other holometabolous insects, the butterfly's life cycle consists of four parts: egg, larva, pupa and adult. Most species are diurnal. Butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. Butterflies comprise the true butterflies (superfamily Papilionoidea), the skippers (superfamily Hesperioidea) and the moth-butterflies (superfamily Hedyloidea). All the many other families within the Lepidoptera are referred to as moths. The earliest known butterfly fossils date to the mid Eocene epoch, between 40–50 million years ago.
Butterflies exhibit polymorphism, mimicry and aposematism. Some, like the Monarch, will migrate over long distances. Some butterflies have evolved symbiotic and parasitic relationships with social insects such as ants. Some species are pests because in their larval stages they can damage domestic crops or trees; however, some species are agents of pollination of some plants, and caterpillars of a few butterflies (e.g., Harvesters) eat harmful insects. Culturally, butterflies are a popular motif in the visual and literary arts.