Butterfly

Intruduction

 Butterflies are part of the class of insects in the order Lepidoptera, along with the moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The group comprises the large superfamily Papilionoidea, along with two smaller groups, the skippers (superfamily Hesperioidea) and the moth-butterflies (superfamily Hedyloidea). Butterfly fossils date to the Palaeocene, about 56 million years ago.

Life cycle of Butterfly

  
Butterflies have the typical four-stage insect life cycle. Winged adults lay eggs on the food plant on which their larvae, known as caterpillars, will feed. The caterpillars grow, sometimes very rapidly, and when fully developed pupate in a chrysalis. When metamorphosis is complete, the pupal skin splits, the adult insect climbs out and, after its wings have expanded and dried, it flies off. Some butterflies, especially in the tropics, have several generations in a year, while others have a single generation, and a few in cold locations may take several years to pass through whole their life cycle.

Systematics and Species

 
Butterflies are often polymorphic, and many species make use of camouflage, mimicry and aposematism to evade their predators. Some, like the monarch and the painted lady, migrate over long distances. Some butterflies have parasitoidal relationships with organisms including protozoans, flies, ants, and other invertebrates, and are predated by vertebrates. Some species are pests because in their larval stages they can damage domestic crops or trees; other 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.

Etymology

The original "butter-fly"? A male brimstone (Gonepteryx rhamni) in flight

The Oxford English Dictionary derives the word straightforwardly from Old English butorflēoge, butter-fly; similar names in Old Dutch and Old High German show that the name is ancient. A possible source of the name is the bright yellow male of the brimstone Gonepteryx rhamni; another is that butterflies were on the wing in meadows during the spring and summer butter season while the grass was growing.^[1][2]

Taxonomy and phylogeny

Further information: Prehistoric Lepidoptera 

                                                                               

Prodryas persephone, a Late Eocene butterfly from the Florissant Fossil Beds. 1887 engraving

Lithopsyche antiqua, an Early Oligocene butterfly from the Bembridge Marls, Isle of Wight. 1889 engraving

 

 

The earliest Lepidoptera fossils are of a small moth, Archaeolepis mane, of Jurassic age, around 190 million years ago (mya).^[3][4] Butterflies evolved from moths, so while the butterflies are monophyletic (forming a single clade), the moths are not. The oldest butterflies are from the Palaeocene MoClay or Fur Formation of Denmark. The oldest American butterfly is the Late Eocene Prodryas persephone from the Florissant Fossil Beds.^[5][6]
Traditionally, the butterflies have been divided into the superfamily Papilionoidea and the smaller groupings of the Hesperioidea (skippers) and the more moth-like Hedyloidea of America. Phylogenetic analysis suggests that the traditional Papilionoidea is paraphyletic with respect to the other two groups, so they should both be included to form a single butterfly group, the clade Rhopalocera.^[7][8]

Biology

The wings of butterflies, here  Inachis io, are covered with   coloured scales

General description

Butterfly antennal shapes, mainly clubbed, unlike those of moths. Drawn by C. T. Bingham, 1905

Further information: Glossary of Lepidopteran terms and Comparison of butterflies and moths

Unlike butterflies, most moths (like Laothoe populi) fly by night and hide by day.

Butterfly adults are characterized by their four scale-covered wings, which give the Lepidoptera their name (Ancient Greek λεπίς lepís, scale + πτερόν pterón, wing). These scales give butterfly wings their colour: they are pigmented with melanins that give them blacks and browns, as well as uric acid derivatives and flavones that give them yellows, but many of the blues, greens, reds and iridescent colours are created by structural coloration produced by the micro-structures of the scales and hairs.^{[9][10][11][12]}
As in all insects, the body is divided into three sections: the head, thorax, and abdomen. The thorax is composed of three segments, each with a pair of legs. In most families of butterfly the antennae are clubbed, unlike those of moths which may be threadlike or feathery. The long proboscis can be coiled when not in use for sipping nectar from flowers.^[13]
                                                                        

Distribution and migration

See also lists of butterflies of Australia (Tasmania, Victoria), Britain, India, Minorca, North America, Taiwan, Trinidad and Tobago

Further information: Lepidoptera migration, Insect migration and Animal navigation

Butterflies are distributed worldwide except Antarctica, totalling some 18,500 species.^[17] Of these, 775 are Nearctic; 7,700 Neotropical; 1,575 Palearctic; 3,650 Afrotropical; and 4,800 are distributed across the combined Oriental and Australian/Oceania regions.^[17] The monarch butterfly is native to the Americas, but in the nineteenth century or before, spread across the world, and is now found in Australia, New Zealand, other parts of Oceania, and the Iberian Peninsula. It is not clear how it dispersed; adults may have been blown by the wind or larvae or pupae may have been accidentally transported by humans, but the presence of suitable host plants in their new environment was a necessity for their successful establishment.^[18]