My research program seeks to understand the factors that contribute to differentiation in floral traits across biological scales, from genomics to community dynamics.
To address my questions, I use a diversity of tools (high throughput chemical analysis of volatile organic compounds, geometric morphometrics, stable isotope analysis, and comparative genomics and transcriptomics) and approaches (field experiments, greenhouse common gardens, meta-analyses).
A conceptual figure for my postdoc project.
As a postdoc with Magne Friberg and Anna Runemark at Lund University, I will be investigating the factors that generate and maintain variation in a complex trait—floral scent—that mediates many interactions between plants and insects and can exhibit substantial variation within species. My work will will leverage and develop an emerging model system for plant evolution, the alpine rock cress (Arabis alpina), through three sets of studies: (1) computational genomic studies of coding genetic divergence and in patterns of gene expression; (2) a large-scale field experiment of the agents of selection in populations of A. alpina across Europe; (3) insect behavior assays that will determine the targets of phenotypic selection on floral scent. These studies will test hypotheses regarding the agents and targets of selection, and the consequences of variation in selection on genetic architecture.
Arabis alpina (A) exhibits variation in floral scent across and within populations, regions, and mating systems (B & C).
Clarkia unguiculata and Clarkia cylindrica in full bloom in Kern County, California in 2017.
My Ph.D work in Monica Geber’s lab at Cornell University focused on how species interactions in communities affect the evolution of plant traits, including morphology (Eisen and Geber 2018, Eisen et al. 2020), phenology (Eisen et al. 2019), floral scent (Eisen et al. 2021), and physiology (in prep!). Specifically, I was interested in how competition or facilitation among plants that share pollinators could lead to trait differentiation and variable patterns of selection. I worked in the southern foothills of the Sierra Nevada, where hillsides can have one to four outcrossing species in the genus Clarkia that share solitary bee pollinators.
Through greenhouse- and field-based studies, I found that floral traits vary with the species composition of the community in patterns that are consistent with character displacement; I also found evidence for variation in the strength of contemporary natural selection on floral traits across communities and years.
You can also read about other collaborative projects and past research here.