Abstract Detail

Evolutionary History, Biogeography, and Floral Morphometrics of Salvia (Lamiaceae)

Kriebel, Ricardo [1], Drew , Bryan T [2], Sytsma, Kenneth J. [1].

The evolution of complex shapes in the flowers of Salvia (Lamiaceae) and their relationship to geography and pollination.

Salvia (Lamiaceae), with over 1000 species and diversity hotspots on five continents, is one of the largest genera of plants. Sages are famous for their showy flowers that have evolved a staminal lever for nototribic pollen placement several times independently. The pollination biology of many species in the genus has been studied and which has led to a key hypothesis: pollinator-mediated natural selection involving transitions from bee to bird pollination are correlated to species diversification in Salvia. Less known is the frequency of transitions between pollinators in the genus, and the effect that they have on flower morphology. To test the hypothesis that changes in flower morphology are the result of pollinator-mediated natural selection, we quantified the shape of the corolla, anther connective (which corresponds to the staminal lever in most species), style and stigma. We then evaluated these shapes by geography and pollinator using a Salvia-wide phylogenetic framework. To this end, we generated a database of outlines of these structures for morphometric analyses by mining the literature as well as scanning fresh material in botanical gardens and in the field. We extracted shape information from the structures using elliptic Fourier analysis. We also conducted ancestral state reconstruction of pollinators on a dated phylogeny of Salvia that includes more than half of the genus and used comparative methods to test for shifts in morphology possibly associated to changes in pollinators. Between 25-50% of the species in the genus were present in these analyses. We found differences in the morphology of New World versus Old World taxa and these differences are partly explained by differences in pollinators. We also found unique areas of morphospace only explored in some biogeographical areas. Ancestral state reconstruction of pollinator suggests bird pollination evolved from bee pollination about six times (three of which are hummingbirds), and that the only large clade associated with hummingbirds is subgenus Calosphace. Within this subgenus, bee pollination then re-evolved many more times. Shifts to straight anther connectives and styles were detected near the MRCA of subg. Calosphace, providing morphological evidence of the early acquisition of hummingbird pollination in this clade. We discuss the evolutionary significance of these and other shifts in floral morphology using the chronograms and area reconstructions of both sages and hummingbirds.

1 - University Of Wisconsin, Department Of Botany, Birge Hall, 430 Lincoln Drive, Madison, WI, 53706, United States
2 - University of Nebraska-Kearney, Biology, 2401 11th Ave, Kearney, NE, 68849, USA

Comparative methods.

Presentation Type: Colloquium Presentations
Abstract ID:465
Candidate for Awards:None

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