Experimental Evolutionary Community Ecology
My research aims to disentangle interactions among ecological and evolutionary processes to better understand how they ultimately respond to disturbances. A central focus of my work is to understand how evolution, including very rapid evolution, and eco-evolutionary feedbacks (the blue and green arrows below) can drive population and community dynamics in plant-insect systems. To do so I utilise complementary methods including experimental evolution in field communities, community manipulations, phylogenetic comparative analyses, and modelling.
Reciprocal Interactions between Rapid Evolution and Ecological Dynamics
We now have numerous examples of evolution occurring over ecological timescales. This convergence of timescales creates the opportunity for eco-evolutionary feedbacks, wherein rapid evolutionary changes and ecological dynamics can reciprocally impact each other leading to qualitatively different outcomes. Most of our knowledge on this topic however, is limited to simplified laboratory systems. My general objective is to utilise experimental evolution in multiple complementary field systems to address:
1) How does contemporary evolution drive, and is driven by, concurrent population dynamics?
2) What is the role and importance of rapid evolution in shaping species interactions and community dynamics?
3) Under what conditions do eco-evolutionary feedbacks promote or hinder adaptation to environmental change?
In my Ph.D. I conducted experimental evolution in field populations of green peach aphids and found very strong effects of evolution on population dynamics. Further experiments revealed that evolutionary dynamics are altered by density providing evidence of an eco-evolutionary feedback loop. In my current postdoctoral position at ETH Zürich, I am conducing field experimental evolution utilising sexually reproducing Drosophila melanogaster to explore eco-evolutionary dynamics during seasonal climatic adaptation. In addition Simon Hart and I are utilising Duckweeds (aquatic floating plants) to test a number of hypotheses in evolutionary community ecology.
The Impacts of Crop Domestication on Plant-Herbivore Interactions
How has human domestication of crops altered their ability to resist pests? Does domestication alter the evolutionary dynamics of their pests?
The domestication of crops can be seen as a large scale evolution experiment replicated hundreds of times. Artificial selection for yield is thought to reduce their ability to invest in defence. To test this hypothesis we used dozens of independent domestication events, each represented by a crop species and a wild-relative (ancestor). We compared how each species could resist two generalist herbivores and examined numerous plant resistant traits. We then utilised comparative experimental evolution to assess whether herbivores can more rapidly adapt to crops or wild plants. We are now continuing this exploration with a meta-analysis to broaden and synthesize our understanding of these processes.
Phenotypic Plasticity and Coexistence
How is species coexistence mediated by phenotypic plasticity?
Developmental plasticity can lead to individuals having very different phenotypes. Sometimes this occurs in response to the presence of competing species. Using a systems of annual plants I am testing how plasticity impacts competitive ability and niche differentiation among species and ultimately whether it promotes or prevents coexistence.
Current Collaborators: Jonathan Levine
Macroevolutionary Patterns of Herbivory
How much do herbivores consume?
What are the macroecological and macroevolutionary patterns of herbivory?
Does evolutionary history and plant traits help predict global patterns of herbivory?
Herbivory is both a major conduit of nutrients and energy in ecosystems as well as a major driver of plant diversification. In order to address numerous questions and hypotheses related to these important plant-herbivore interactions we assembled a massive database of published measures of herbivory that can be update and expanded (Turcotte et al., Ecology, 2014). Our first analysis revealed that average rates of herbivory are lower than previously expected. In addition phylogenetic comparative analyses revealed that evolutionary history and the presence of certain plant traits explain significant portions of variation in global herbivory.