Danaus petilia, the lesser wanderer, is a species of butterfly in the nymphalid Danainae subfamily.

[2] Previously considered a subspecies of Danaus chrysippus,[3] this species came about through allopatric speciation.

The deep sea barrier called Lydekker's Line, located by the Molluccas and the Sahul Shelf, was what separated Danaus petilia from Danaus chrysippus cratippus.

[3] Its caterpillars feed on native and introduced cotton bush species.

[2] A common butterfly with nomadic populations, particularly in central Australia where many native host plants die of during dry periods, and in south eastern Australia where it is too cold for them in winter.