Butterfly

A butterfly is a flying insect of the order Lepidoptera (as are Moths),
usually with striking colours and patterns on its wings.

People who study or collect butterflies are called lepidopterists.

Etymology

An erroneous etymology claims that the word butterfly came from a shift of
letters in "flutterby"; however, the old English word was buttorfleoge and a
similar word occurs in Dutch, apparently because butterflies were thought to
steal milk.

The four stages in the lifecycle of a butterfly

Unlike most insects they do not have a nymph period, but have a pupal stage
between the larva and the adult stage (the imago).

   * Egg
   * Larva, known as a caterpillar
   * Pupa / chrysalis
   * Adult butterfly / imago

Egg

Butterfly eggs consist of a hard-ridged outer layer of shell, called the
chorion, lined with a thin coating of wax which prevents the egg from drying
out before the larva has fully developed. Each egg has a number of tiny
funnel-shaped openings at one end, called micropyles. The purpose of the
holes is to allow sperm to enter and to fertilize the egg. Butterfly and
moth eggs vary greatly in size between species, but they are all spherical
or ovate.

Larva

Larvae, or caterpillars, are multilegged eating machines. They live on plant
leaves and spend practically all their time eating. As they grow they shed
their skin several times.

Pupa

When the larva has eaten enough it will will either spin a coccoon or form a
chrysalis. The larva usually moves to the underside of a leaf. To form a
coccoon it spins a silk-like thread around itself. A chrysalis is formed by
hardening bodily secretions. A larva completely covered by a coccoon or
chrysalis is called a pupa. Inside its protective shell the larva will
transform into a butterfly (or moth).

Butterfly

As lepidoptera, butterflies have four wings, but unlike moths, the fore and
hindwings are not hooked together, permitting of 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 can not 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 colour, habits, and pupating appearance.
See the difference between a butterfly and a moth.

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.

Species

There are between 15,000 and 20,000 species of butterflies worldwide. Some
species include:

   * Small Tortoiseshell, Nymphalis urticae
   * 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

Survival

Butterflies (and their stages) have many natural enemies such as:

   * Ants
   * Beetles
   * Birds
   * Flies
   * Lizards, frogs, and toads
   * Praying mantids
   * Spiders
   * Wasps

Ants

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.

Birds

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.

Field guides to North American butterflies

   * Butterflies of North America, Jim P. Brock and Kenn Kaufman (2003)
   * Butterflies through Binoculars: The East, Jeffrey Glassberg (1999)
   * Butterflies through Binoculars: The West, Jeffrey Glassberg (2001)
   * A Field Guide to Eastern Butterflies, Paul Opler (1994)
   * A Field Guide to Western Butterflies, Paul Opler (1999)
   * Peterson First Guide to Butterflies and Moths, Paul Opler (1994)

Other meanings

   * The butterfly stroke is a type of swimming stroke, in which the arms
     are thrown forward together out of the water while the feet kick up and
     down.
   * In chaos theory, the term butterfly effect is used to describe certain
     chaotic phenomena.
   * A butterfly nut is a fastening, for use with a bolt, with a pair of
     metal "wings".
   * To have butterflies in your stomach is to be very nervous.
   * Butterflies was a TV series in the UK.