Vanessa cardui Vanessa cardui Vanessa cardui is a well-known colorful butterfly, known as the painted lady, or in North America as the cosmopolitan. "V. cardui" is one of the most widespread of all butterflies, found on every continent except Antarctica and South America. In Australia, "V. cardui" has a limited range around Bunbury, Fremantle, and Rottnest Island. However, its close relative, the Australian painted lady ("V. kershawi", sometimes considered a subspecies) ranges over half the continent. Other closely related species are the American painted lady ("V. virginiensis") and the West Coast lady ("V. annabella"). "V. cardui" occurs in any temperate zone, including
Brachycaudus cardui "B. cardui" are usually attended by ants which feed on the honeydew the aphids produce and drive away predators. Researchers found that in a damp meadow which contained ragwort ("Jacobaea vulgaris") but no ants, although winged "B. cardui" arrived at the site, they failed to establish colonies despite an abundance of the host plant. In an experimental habitat, colonies of "B. cardui" on "J. vulgaris" flourished when ants were present but died out if ants were excluded. Infestation with "B. cardui" causes the margins of affected leaves to roll up. This aphid is a vector of plum pox, a serious