Ecology research

Photo: Edward Rooks, via Wikimedia Commons, CC BY-SA 4.0

My research focuses broadly on how variation contributes to population and community ecology, and how interspecific interactions affect ecological and evolutionary processes at larger scales.   My work uses both field experiments and mathematical/computing tools to extrapolate interactions such as host-pathogen interactions and mutualism to larger contexts such as population and community dynamics and evolutionary change.

Previous projects include a postdoc with Greg Dwyer at the University of Chicago, and my PhD work with Bill Morris at Duke University.  Current ecology research collaborations include a project on evolution of virulence with Dana Hawley at Virginia Tech.  See below for some current and prior projects.

Disease ecology

Processes maintaining diversity in an insect viral pathogen

I used a combination of field experiments and differential equation models to understand what maintains diversity in a pathogen that infects gypsy moth (Lymantria dispar) larvae.  Phenotypic variation is common in most pathogens, yet the mechanisms that maintain this diversity are still poorly understood.  We found evidence that host heterogeneity in susceptibility may help maintain coexistence of multiple pathogen strains by introducing two alternate strategies for the pathogen: a low-transmission, low-variability strain is able to coexist with the high-transmission type favored by classical non-heterogeneity models.

In the same system, we found evidence of a cost of virulence in the overwinter environmental transmission that might also help maintain pathogen polymorphism.  This cost could impose an upper limit to virulence even in a highly virulent pathogen

This work was conducted in collaboration with my previous postdoctoral advisor, Greg Dwyer.

For more details, see:

Fleming-Davies, Arietta E., Vanja Dukic, Viggo Andreasen, and Greg Dwyer. 2015. Effects of host heterogeneity on pathogen diversity and evolution. Ecology Letters, 18:1252-1261.

Fleming-Davies, Arietta E. and Greg Dwyer. 2015. Phenotypic variation in environmental persistence of a baculovirus and the cost of virulence. The American Naturalist, 186:797-806.

Host-pathogen coevolution

Photo by B. Brachi

Phenotypic variation in a pathogen is closely tied to host-pathogen coevolution. I recently worked with a colleague, David Paez, to look at how exposure to different virus doses and isolates influences the life history of the gypsy moth.  I am currently working on a project to model within-host dynamics of the gypsy moth virus and host immune with partially observed Markov process models, in order to ask to what extent stochasticity in within-host processes leads to variation in pathogen and host fitness. Our work on host-pathogen coevolution also led to an independent project for an undergraduate student on detecting genotype by genotype interactions between host and pathogen in this system

This work was conducted in collaboration with my previous postdoctoral advisor, Greg Dwyer.

For more details, see:

Paez, David J.*, Arietta E. Fleming-Davies*, and Greg Dwyer. 2015. Effects of pathogen exposure on life-history variation in the gypsy moth (Lymantria dispar).
Journal of Evolutionary Biology, 28: 18281839.
*equally contributing authors

Hudson, Asher.*, Arietta E. Fleming-Davies, David J. Paez and Greg Dwyer.  Genotype by genotype interactions between an insect and its pathogen. Accepted, Journal of Evolutionary Biology.
*undergraduate mentee

Evolution of virulence in an emerging pathogen

Photo by D. Hawley

I am currently collaborating with Dana Hawley at Virginia Tech on a project modeling evolution of virulence in her house finch-mycoplasma system.  We are using experimental data from her house finch-mycoplasma system to model how repeated exposure to mycoplasma on bird feeders could contribute to the evolution of virulence in this emerging pathogen.

 

For more details, see: 

Fleming-Davies, Arietta E.*, Paul D. Williams*, André A. Dhondt, Andrew P. Dobson, Wesley M. Hochachka, Ariel E. Leon, David H. Ley, Erik E. Osnas, and Dana M. Hawley. 2018. Incomplete host immunity favors the evolution of virulence in an emergent pathogen. Science, 359: 1030-1033.
*equally contributing authors