Vanessa cardui
Encyclopedia
Vanessa cardui is a well-known colourful butterfly
Butterfly
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...

, known as the Painted Lady, or in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 as the Cosmopolitan. This butterfly has a strange pattern of flying in a sort of screw shape.

Distribution

V. cardui is one of the most widespread of all butterflies, found on every continent except Antarctica and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. In Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, V. cardui has a limited range around Bunbury
Bunbury, Western Australia
The port city of Bunbury is the third largest city in Western Australia after the State Capital Perth and Mandurah. It is situated south of Perth's central business district...

, Fremantle
Fremantle, Western Australia
Fremantle is a city in Western Australia, located at the mouth of the Swan River. Fremantle Harbour serves as the port of Perth, the state capital. Fremantle was the first area settled by the Swan River colonists in 1829...

 and Rottnest Island
Rottnest Island
Rottnest Island is located off the coast of Western Australia, near Fremantle. It is called Wadjemup by the Noongar people, meaning "place across the water". The island is long, and at its widest point with a total land area of . It is classified as an A Class Reserve and is managed by the...

. However, its close relative, the Australian Painted Lady
Australian painted lady
Vanessa kershawi, commonly known as the Australian Painted Lady, is a butterfly that is mostly confined to Australia, although westerly winds have dispersed it to islands east of Australia, including New Zealand. During spring adult butterflies migrate south in large numbers from northern states of...

 (Vanessa kershawi, sometimes considered a subspecies) ranges over half the continent. Other closely related species are the American Painted Lady
American Painted Lady
The American Painted Lady or American Lady is a butterfly found throughout North America.Vanessa virginiensis lives in flowery habitats, usually in mountains. The larvae feed on various Asteraceae, especially the cudweeds of genus Gnaphalium...

 (Vanessa virginiensis), and the West Coast Lady
West Coast Lady
The West Coast Lady is one of three North American species of brush-footed butterflies known colloquially as the "painted ladies". V. annabella occurs throughout much of the western US and south western Canada. The other two species are the cosmopolitan Vanessa cardui and the eastern Vanessa...

 (Vanessa annabella).

Migration

Vanessa cardui occurs in any temperate zone, including mountains in the tropics. The species is resident only in warmer areas, but migrates in spring, and sometimes again in autumn. It migrates from North Africa and the Mediterranean to Britain in May and June, but for decades natualists have debated whether the offspring of these immigrants ever make a southwards return migration. Recent research suggests that British painted ladies do undertake an autumn migration. Using an entomological radar, scientists at Rothamsted Research provided evidence that autumn migrations take place at high altitude, which could be why these migrations are seldom witnessed.

Relationship with humans

Vanessa cardui butterflies are raised in many pre-school classrooms to demonstrate the life cycle of a butterfly. Naturally, this is one reason they are so popular amongst children. They are also often found in science fair projects.

Life cycle

The egg takes 3 to 5 days to hatch. The eggs are tiny, as tiny as a sugar crystal. They are green and can be observed best with a magnifying glass. The caterpillar takes 7–11 days to turn into a chrysalis. At this stage the caterpillar eats a great deal of mallow and other types of plants. Before entering its chrysalis, the caterpillar will moult several times because of how quickly it grows in such a short period of time. The moult appears as a black speck, what looks like dirt, near the caterpillar. Many people believe this to be the excretion of the caterpillar, but it is truly the moult (the skin the caterpillar has grown out of). It takes 7–11 days for the chrysalis to turn into a butterfly. The painted lady butterfly travels around 1000 miles in its life. Its wing span is 2 inches. The painted lady caterpillar is black with spiked skin.

Host plants

Larvae feed on Asteraceae
Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

spp., including Cirsium
Cirsium
Cirsium is a genus of perennial and biennial flowering plants in the Asteraceae, one of several genera known commonly as thistles. They are more accurately known as Plume thistles. These differ from other thistle genera in having feathered hairs to their achenes...

, Carduus
Carduus
Carduus is a genus of about 90 species of thistles in the family Asteraceae, native to Europe, Asia and Africa. Carduus is Latin for a thistle....

,Centaurea
Centaurea
Centaurea is a genus of between 350 and 600 species of herbaceous thistle-like flowering plants in the family Asteraceae. Members of the genus are found only north of the equator, mostly in the Eastern Hemisphere; the Middle East and surrounding regions are particularly species-rich...

, Arctium, Helianthus
Helianthus
Helianthus L. is a genus of plants comprising 52 species in the Asteraceae family, all of which are native to North America, with some species Helianthus L. is a genus of plants comprising 52 species in the Asteraceae family, all of which are native to North America, with some species Helianthus...

, and Artemisia
Artemisia
- Botany :* Artemisia , a genus of plants including the sagebrush and wormwood- Geography :* Artemisia Geyser in Yellowstone National Park* Artemissia, Messinia, a Greek village west of Taygetus mountain in the Peloponnese...

spp.

External links

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