Vanessa cardui of the sky, implying the use of a solar compass to orient its migratory direction and maintain a straight flight path. "V. cardui" displays a unique system of continuous mating, throughout all seasons, including the winter. This may be attributed to its migratory patterns, thus significantly affecting its mating behavior. During European migrations, the butterflies immediately begin to mate and lay eggs upon arrival in the Mediterranean in the spring, starting in late May. In the United States, painted lady butterflies migrating towards the north experience poor mating conditions, and many butterflies have limited breeding capabilities. The "local adult generation"
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