Butterflies are part of the class of Insects in the order Lepidoptera. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering fl ight. The group comprises the true butterflies, the skippers and the moth-butterflies. Butterfly fossils date to the mid Eocene epoch, 40–50 million years ago.
Butterflies exhibit polymorphism, mimicry and aposematism. Some, like the Monarch, will migrate over long distances. Some butterflies have parasitic relationships with organisms including protozoans, flies, ants, other invertebrates, and vertebrates. 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 eat harmful insects. Culturally, butterflies are a popular characters in the visual and literary arts.
The Oxford English Dictionary derives the word from a combination of butter and fly. It adds: "the reason of the name is unknown", and refers to Hensleigh Wedgwood, who "points out a Dutch synonym boterschĳ te in Kilian, which suggests that the insect was so called from the appearance of its excrement". Donald Ringe writes that the name is derived from Middle English buterflie, butturflye, boterflye, from Old English butorflēoge, buttorflēoge, buterflēoge, perhaps a compound of butor (beater), mutation of bēatan (to beat), and flēoge (fly).
Butterflies in their adult stage can live from a week to nearly a year depending on the species. Many species have long larval life stages while others can remain dormant in their pupal or egg stages and thereby survive winters. Butterflies may have one or more broods per year. The number of generations per year varies from temperate to tropical regions with tropical regions showing a trend towards multivoltinism.
Butterflies feed primarily on nectar from flowers. Some also derive nourishment from pollen tree sap, rotting fruit, dung, decaying flesh, and dissolved minerals in wet sand or dirt. Butterflies are important as pollinators for some species of plants although in general they do not carry as much pollen load as bees. They are however capable of moving pollen over greater distances. Flower constancy has been observed for at least one species of butterfly.
Adult butterflies consume only liquids, ingested through the proboscis. They sip water from damp patches for hydration and feed on nectar from flowers, from which they obtain sugars for energy, and sodium and other minerals vital for reproduction. Several species of butterflies need more sodium than that provided by nectar and are attracted by sodium in salt; they sometimes land on people, attracted by the salt in human sweat. Some butterflies also visit dung, rotting fruit or carcasses to obtain minerals and nutrients. In many species, this mud-puddling behaviour is restricted to the males, and studies have suggested that the nutrients collected may be provided as a nuptial gift along with the spermatophore, during mating.
Butterflies use their antennae to sense the air for wind and scents. The antennae come in various shapes and colours; the hesperids have a pointed angle or hook to the antennae, while most other families show knobbed antennae. The antennae are richly covered with sensory organs known as sensillae. A butterfly's sense of taste, 200 times stronger than a human's, is coordinated by chemoreceptors on the tarsi, or feet, which work only on contact, and are used to determine whether an egg-laying insect's offspring will be able to feed on a leaf before eggs are laid on it. Many butterflies use chemical signals, pheromones, and specialized scent scales and other structures are developed in some species.
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Butterflies can influence the environment negatively when
- some of them have parasitic relationships with organisms.
- they belong to pestilential species.
- they sweep away entire crops.
- they eat vermins.
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