Tuesday, October 16, 2012

Butterfly

Despite their small size, butterflies and moths are some of the World's most wondrous animals. Their beauty, seemingly miraculous metamorphosis, and apparently carefree flight all spark our imaginations.

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.

Butterfly larvae, or caterpillars, consume plant leaves and spend practically all of their time in search of food. Although most caterpillars are herbivorous, a few species such as Spalgis epius and Liphyra brassolis are entomophagous (insect eating).

Some larvae, especially those of the Lycaenidae, form mutual associations with ants. They communicate with the ants using vibrations that are transmitted through the substrate as well as using chemical signals.[4][5] The ants provide some degree of protection to these larvae and they in turn gather honeydew secretions.

Caterpillars mature through a series of stages called instars. Near the end of each instar, the larva undergoes a process called apolysis, in which the cuticle, a tough outer layer made of a mixture of chitin and specialized proteins, is released from the softer epidermis beneath, and the epidermis begins to form a new cuticle beneath. At the end of each instar, the larva moults the old cuticle, and the new cuticle expands, before rapidly hardening and developing pigment. Development of butterfly wing patterns begins by the last larval instar.

Butterfly caterpillars have three pairs of true legs from the thoracic segments and up to 6 pairs of prolegs arising from the abdominal segments. These prolegs have rings of tiny hooks called crochets that help them grip the substrate.

Some caterpillars have the ability to inflate parts of their head to appear snake-like. Many have false eye-spots to enhance this effect. Some caterpillars have special structures called osmeteria which are everted to produce smelly chemicals. These are used in defense.

Host plants often have toxic substances in them and caterpillars are able to sequester these substances and retain them into the adult stage. This makes them unpalatable to birds and other predators. Such unpalatibility is advertised using bright red, orange, black or white warning colours, a practice known as aposematism. The toxic chemicals in plants are often evolved specifically to prevent them from being eaten by insects. Insects in turn develop countermeasures or make use of these toxins for their own survival. This "arms race" has led to the coevolution of insects and their host plants.

Queen Alexandra's Birdwing is the biggest butterfly in the world, with a wingspan up to 1 ft (30 cm) wide. This rare, tropical butterfly is from a lowland coastal rainforest in New Guinea. This huge butterfly is on the US Endangered Species List. Its rainforest habitat is being reduced as oil palm plantations are created.

This enormous butterfly was named by Alfred S. Meek (in 1907) to honor Queen Alexandra (1844-1925), the Danish wife of King Edward VII of England (1841-1910).

The Zebra Swallowtail butterfly is a common butterfly with distinctive black and white markings and elongated tails on its hindwings It also has some small red and blue hindwing markings and strongly-scalloped hindwing margins. The caterpillar is yellow-green with black and yellow stripes. The Zebra Swallowtail has a wingspan of about 3.75-4.5 inches (9.5-11.5 cm).



They are called swallowtails because they have long "tails" on their hindwings which look a bit like the long, pointed tails of swallows (a type of bird).

The Tiger Swallowtail butterfly (Papilio glaucas) is a strong flier with distinctive yellow and black striped markings on its wings and body (some females are brown or black, mimicking the poisonous pipevine swallowtail). This relatively common butterfly has a wingspan of 3.5-6.5 inches (9-16.5 cm). Southern subspecies are larger than the northern ones.


These butterflies are called swallowtails because they have long "tails" on their hindwings which look a bit like the long, pointed tails of swallows (a type of bird).

No comments: