MULTIPLE ORIGINS OF THE YUCCA-YUCCA MOTH ASSOCIATION

The association of species of yucca and their pollinating moths is con sidered one of the two classic cases of obligate mutualism between flo ral hosts and their pollinators. The system involves the active collec tion of pollen by females of two prodoxid moth genera and the subseque nt purposeful placement of the pollen on conspecific stigmas of specie s of Yucca. Yuccas essentially depend on the moths for pollination and the moths require Yucca ovaries for oviposition. Because of the speci ficity involved, it has been assumed that the association arose once, although it has been suggested that within the prodoxid moths as a who le, pollinators have arisen from seed predators more than once. We sho w, by using phylogenies generated from three molecular data sets, that the supposed restriction of the yucca moths and their allies to the A gavaceae is an artifact caused by an incorrect circumscription of this family. In addition we provide evidence that Yucca is not monophyleti c, leading to the conclusion that the modern Yucca-yucca moth relation ship developed independently more than once by colonization of a new h ost.