Clouded Yellow
Photo: Lalit Shastri Profile by CREW This genus occurs throughout the Americas , Africa , China and India . Their caterpillars feed on certain Fabaceae , for example vetches ( Vicia ). While most are thus beneficial by keeping weeds at bay, some occasionally become nuisance pests on crops like alfalfa . In some species, the wings of males have brilliant ultraviolet reflection, while those of females do not.