Vanessa cardui (Linnaeus, 1758)

Vanessa cardui, also called the Painted Lady or the Cosmopolitan(in North America), is a popular colourful butterfly species that shows a characteristic strange screw shaped flight pattern.

Eggs of the Painted Lady are tiny, green and ribbed. Caterpillars emerge from the capped part of the egg. When they emerge, caterpillars are small, black and begin to eat immediately. As they grow, they shed their skin thrice, called instars. As their development progresses, the caterpillar becomes more spiky. These spikes do not contain poison and are not sharp. If under stress, the caterpillar will sometimes shed into a fifth instar, which is a very large caterpillar. The four instars take 7–11 days to turn into a chrysalis. The caterpillar then spins a patch of silk and attaches its hind end to the silk. At this point it begins changing internally, forming a "j" shape. The chrysalis is very soft at first and will dent if resting on a hard surface. After hardening, the chrysalis will crack if dropped or struck. The chrysalis can be dark or light colored depending on conditions during development of the caterpillar. It takes 7–11 days for the chrysalis to turn into a butterfly. When emerging from the chrysalis the butterfly pumps its wings with fluid to expand them. This happens within a few minutes of emerging or cannot happen at all. Once the wings are expanded they are still soft for up to a day. Initially the butterfly prefers not to move as its wings harden, but after the wings harden for a few hours the painted lady will become incredibly sensitive to movement and will damage its still soft wings when frightened.

Mating System: polygynous A green, barrel-shaped egg is laid singly on a host plant. The color of the larva varies from chartreuse with black marbling to a purple with a yellow hue. Breeding season: All year in the tropics, spring and summer in cooler climates. Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; sexual ; fertilization (Internal); oviparous Parental Investment: no parental involvement.

A long-distance migratory species, the Painted Lady shows a wide range, but is resident only in warmer areas and migrates in spring and sometimes again in autumn. Autumn migrations occur at high altitudes and are seldom witnessed.

Lifespan depends on the climate, but is probably never more than one winter. Only adults survive through winter, and even then only in mild climates.

55-70 mm

In both sexes, uppersides are reddish yellow with dark brown markings, apical area of forewing with a short post-discal white bar from costa and a pre-apical series of white spots. Hind wing with a series of post-discal dark brown spots and a sub-terminal series of spots, the apices of the veins bearing a dark spot. Fringe of wings white. Under-side: Forewing: as on upperside but paler, the terminal border with white lines. Hind wing: much mottled with dark brown and yellowish white, a post-discal series of black-ringed ocelli with bluish centres, the ocellus in interspace 2 the largest, the terminal border with a yellowish line. Markings very variable.

Larvae of the Painted Lady feed on more than 300 plant species including members of the family Asteraceae such as Cirsium sp, Carduus sp,Centaurea sp, Arctium sp, Helianthus sp. and Artemisia sp. Adults feed on flower nectar and sometimes aphid honeydew.

Larva of Phryxe vulgaris is an endoparasitoid of Cynthia cardui larvae. Vanessa cardui is prey to Aves, Araneae, Hymenoptera and Formicidae.

Found almost everywhere, this species prefers brightly lighted and open environments like open grasslands and flowery meadows of mid-high altitude. Marshes, dunes, and thorn scrubs also attract the Painted Lady.

10,000 to >1,000,000 individuals. Populations fluctuate greatly.

Common

Raised in many preschool and elementary classrooms to demonstrate the life cycle of a butterfly, Vanessa cardui is very popular amongst children and is often used in science fair projects.