Timing of rapid diversification and convergent origins of active pollination within Agavoideae (Asparagaceae)

PREMISE OF THE STUDY: Yucca species are ideal candidates for the study of coevolution due to the obligate mutualism they form with yucca moth pollinators (genera Tegeticula and Parategeticula). Yuccas are not the only species to exhibit a mutualism with yucca moths; the genus Hesperoyucca is pollinated by the California yucca moth (Tegeticula maculata). Relationships among yuccas, Hesperoyucca, and other members of subfamily Agavoideae are necessary to understand the evolution of this unique pollination syndrome. Here, we investigate evolutionary relationships of yuccas and closely related genera looking at the timing and origin of yucca moth pollination.

METHODS: In this study, we sequenced the chloroplast genomes of 20 species in the subfamily Agavoideae (Asparagaceae) and three confamilial outgroup taxa to resolve intergeneric phylogenetic relationships of Agavoideae. We estimated divergence times using protein-coding genes from 67 chloroplast genomes sampled across monocots to de...