A butterfly is a flying insect of the order Lepidoptera belonging to one of the superfamilies Hesperioidea (the skippers) and Papilionoidea (all other butterflies). Many butterflies have remarkable colors and patterns on their wings. People who study or collect butterflies (or the closely related moths) are called lepidopterists. Butterfly watching is growing in popularity as a hobby.
The four stages in the lifecycle of a butterfly
Unlike many insects, butterflies do not experience a nymph period, but instead go through a pupal stage which lies between the larva and the adult stage (the imago).
- Larva, known as a caterpillar
- Pupa (chrysalis)
- Adult butterfly (imago)
Butterfly eggs consist of a hard-ridged outer layer of shell, called the chorion. This is lined with a thin coating of wax which prevents the egg from drying out before the larva has had time to fully develop. Each egg contains a number of tiny funnel-shaped openings at one end, called micropyles; the purpose of these holes is to allow sperm to enter and fertilize the egg. Butterfly and moth eggs vary greatly in size between species, but they are all either spherical or ovate.
Larvae, or caterpillars, are multi-legged eating machines. They consume plant leaves and spend practically all of their time in search of food. As they mature their skin is shed several times.
When the larva has eaten enough it will form a chrysalis (butterflies do not spin cocoons, moths do.) The larva usually moves to the underside of a leaf. To form a cocoon it spins a silk-like thread around itself. A chrysalis is formed by hardening bodily secretions. A larva completely covered by a cocoon or chrysalis is called a pupa. Inside its protective shell the larva will transform into a butterfly (or moth), a process known as metamorphosis.
The adult, sexually mature stage of the insect is known as the imago. As Lepidoptera, butterflies have four wings that are covered with tiny scale. However, unlike moths, the fore and hindwings are not hooked together, permitting a more graceful flight. A butterfly has six legs. The larva also has six true legs and a number of prolegs. After it emerges from its pupal stage it cannot fly for some time because its wings have not yet unfolded. A newly emerged butterfly needs to spend some time ‘inflating’ its wings with blood and letting them dry, during which time it is extremely vulnerable to predators.
Many species of butterfly are sexually dimorphic. Some butterflies, such as the Monarch butterfly, are migratory.
Butterflies are often confused with moths, but there are a few simple differences between them, including color, habits, and pupating appearance.
Butterflies live primarily on nectar from flowers. Some also derive nourishment from pollen, tree sap, rotting fruit, dung, and dissolved minerals in wet sand or dirt. Butterflies are also pollinators.
Although the butterflies are classified in two superfamilies – Hesperioidea and Papilionoidea – these are sister taxa, so the butterflies collectively are thought to constitute a true clade. Some modern taxonomists place them all in superfamily Papilionoidea, distinguishing the skippers from the other butterflies at the series level only. There is only one family in the Hesperioidea (or series Hesperiiformes), the skipper family Hesperiidae. The families in the Papilionoidea (or Papilioniformes) are:
- Swallowtails and Birdwings, Papilionidae
- Whites or Yellow-Whites, Pieridae
- Blues and Coppers or Gossamer-Winged Butterflies, Lycaenidae
- Metalmark butterflies, Riodinidae
- Snout butterflies, Libytheidae
- Brush-footed butterflies, Nymphalidae
Some older taxonomies recognize additional families, for example Danaidae, Heliconiidae and Satyridae, but modern classifications treat these as subfamilies within the Nymphalidae.
There are between 15,000 and 20,000 species of butterflies worldwide. Some well known species include:
- Small Tortoiseshell, Nymphalis urticae
- Small White, Artogeia rapae
- Green-veined White, Artogeia napi
- Monarch butterfly, Danaus plexippus
- Red Admiral, Vanessa atalanta
- Painted Lady or Cosmopolite, Vanessa cardui
- Peacock, Inachis io
- Xerces Blue, Glaucopsyche xerces
- Gulf Fritillary, Agraulis vanillae
- Black Swallowtail, Papilio polyxenes
- Spicebush Swallowtail, Papilio troilus
- Karner Blue, Lycaeides melissa samuelis (endangered)
- Morpho genus
- Troides genus (birdwings; the largest butterflies)
Butterflies (and their immature stages) have many natural enemies such as:
- Lizards, frogs, and toads
- Praying mantises
Ants will sometimes attack a larva in hordes. However, there are actually some species of ants that keep myrmecophilous (ant loving) butterfly larvae as cattle, taking a larva into their nest, feeding it leaves on one end and milking it for honeydew on the other. This symbiotic relationship can turn to the larvae becoming myrmecophageous (ant-eating). The ants actually tolerate the larvae even while they eat the ant pupae.
Some butterflies have evolved “eye” like markings on their wings, scaring off some birds. Also, since some birds attack the eyes of an animal first, the butterfly has a chance of escaping in the confusion when the bird simply pokes a hole in one of the wings.
An erroneous etymology claims that the word butterfly came from a metathesis of “flutterby”; however, the Old English word was buttorfleoge and a similar word occurs in Dutch, apparently because butterflies were thought to steal milk.