Eco-evolutionary dynamics of pollinator-driven diversification

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Research in my lab maintains a focus on the factors responsible for the wide range in evolutionary success among angiosperm lineages, especially those influenced by pollination, and why they matter for the maintenance of contemporary ecosystems. Over the next five years, my lab will combine phylogenetic comparative approaches with field components and appropriate molecular tools to investigate three major avenues by which pollination influences plant diversification: Theme I Range expansion, trait evolution, and diversification of plant lineages: My lab is currently investigating the influence of range shifts and the accompanying shifts in pollinators on plant speciation. We will pair phylogenetic analyses of diversification and range in Plantaginaceae to estimate the influence of long-distance dispersal to bird pollination. At a more local scale, we are investigating how adaptation to new environments can affect pollinator composition and gene flow between populations within species of Penstemon in the Alberta Rockies. Finally, at a broader scale, we are integrating community ecology with historical biogeography in the ~130 genera where hummingbird pollination has evolved. We will construct dated phylogenies of these lineages to determine (1) what extent parallels in pollinators are commonly aligned with range expansion among members of these disparate clades and 2) whether pollinator specialization is associated with altered rates of diversification. Theme II The influence of trait conservatism and lability in plant diversification: The underlying genomics of traits influences the extent of trait conservatism. My lab is currently investigating the quantitative genetics of ultraviolet (UV) reflectance, a trait considered critical to the pollination success of many species, using Mimulus guttatus as a model system. This study will be extended to investigate how the underlying genetic architecture of a trait influences the rate at which it can evolve. We are conducting analyses of whether (1) the degree of stabilizing selection on a trait is associated with diversification rate and (2) whether the number of genes involved in a trait are associated with evolutionary rates. Theme III Plant-pollinator ecophylogenetics, phylobetadiversity, and ecosystem services: Expanding our previous work on plant phylogenetic community structure, my lab will embark on studies of plant and pollinator betadiversity in temperate and tropical locales. Higher connectance is observed in smaller networks and is associated with higher stability, indicating that specialists potentially destabilize networks and offer limited ecosystem service. We will construct phylogenies for plants and pollinators found throughout the networks, measuring the ecosystem service the pollinator community provides to the plant community in terms of seed set. Novel to this proposal, we will compare the turnover (in terms of betadiversity and phylobetadiversity) in pollinator composition in temperate versus tropical sites and test whether species turnover is associated with the summed contribution of specialists to the ecosystem function of pollination.