Meeting Abstract

113-2   13:45 - 14:00  A comparative approach to understanding floral adaptation to climate and pollinators during Silene diversification Miladin, JR*; Steven, JC; Collar, DC; Christopher Newport University; Christopher Newport University; Christopher Newport University jenna.miladin.17@cnu.edu

Morphological diversification in plant lineages is often a result of abiotic and biotic selective factors that combine to shape evolution of plant organs. Change in a species’ climatic niche can drive leaf and floral trait adaptation, and it can also result in shifts in pollinator community and selection on floral morphology. Although disentangling these effects can be difficult for a lineage that diversifies in a single geographic area, stronger inferences can be drawn when diversification plays out over different continents. We tested associations between climate variables, pollinator identity, and vegetative and floral morphology from 145 species of the genus Silene from both North America and Europe using phylogenetic comparative methods. On both continents, leaf size was smaller in drier habitats. Changes in abiotic environment did not appear to directly influence floral trait evolution in Europe, while larger flowers were associated with warmer habitats in North America, though these variables were also correlated with hummingbird pollination. We also found evidence of climate-pollinator associations that influenced floral traits. In both Europe and North America, the climactic variables that correlate with nocturnal pollination were also the variables that determined the habitat niche of Hadena moths, a known nocturnal Silene pollinator. However, the climatic variables that influence Hadena moth distribution differed between the continents. In addition, nocturnally-pollinated Silene were more likely to have longer internodes and wider flowers than diurnally-pollinated Silene on both continents. These findings suggest that in species radiations on both continents, habitat transitions to new climactic conditions led to a new pollinator community, which then resulted in pollinator-mediated adaptation.