Three cheers to Department of Ecology and Evolutionary graduate students Leslie Decker, Joanna Larson and Marian Schmidt on their Doctoral Dissertation Improvement Grants from the National Science Foundation for 2017 – 2018.

Keep right on cheering for Katherine McLean and Kristel Sanchez, who received fellowships from the NSF Graduate Research Fellowship Program, which provides three years of funding. Their research investigates disease dynamics using host-parasite systems.

The research of these graduate students, with implications for conservation, biodiversity and disease dynamics in a changing world is underway in campus labs, in Midwestern lakes and in sites as far as the rainforest in the Andean foothills of southern Peru.

NSF Doctoral Dissertation Improvement Grants

DDIG: Leslie Decker

Decker’s research will explore how global change alters host immune function and consequent disease dynamics through changes in host diet quality. Her advisor is Professor Mark Hunter.

“The environment within which host and parasite live can have profound impacts on a host’s ability to mitigate the costs of infection at a given parasite load (termed host tolerance) and a parasite’s ability to harm the host (parasite virulence),” explained Decker. “We will examine how dietary effects on host immunity underlie corresponding shifts in host tolerance and parasite virulence using a system with a high degree of dependence on diet: the interaction between the monarch butterfly, Danaus plexippus, and its protozoan parasite, Ophryocystis elektroscirrha (OE).

“Toxic compounds found in the milkweed (Asclepias) plants that monarchs consume convey increased protection against OE. Critically, elevated CO2 alters the medicinal and nutritional quality of milkweed foliage. This research will employ novel chemical techniques to better quantify the diversity and activity of the holistic milkweed chemical profile and relate this information to host and parasite performance under future conditions."

DDIG: Joanna Larson

“Across the tree of life, diet varies widely among species,” said Larson. “Some species have very specialized diets that consist of only one or a few items, while other species appear to eat a broad range of food items. Why some animals have highly specialized diets and how diet changes over deep time scales remain unanswered questions in the field of biology.” Larson’s advisor is Professor Dan Rabosky.

Larson’s project will use frogs as a study system to examine these questions, as well as the relationship between diet ecology and diversification dynamics. “To do so, we will develop new applications of DNA sequencing to generate data on diet from samples collected through intensive fieldwork across the New World and new methods for analyzing complex datasets. This will generate a dataset of prey items identified to species level with information about the relative abundance of each in a frog’s diet. The new methods we develop will be broadly applicable to any system beyond frogs.” Her project will generate large quantities of publicly accessible data for future scientific research into other major evolutionary questions and produce basic natural history data that can be used to inform conservation strategies for endangered frog species.

DDIG: Marian Schmidt

“Bacteria make up the majority of the planetary biodiversity, inhabit almost every corner of our planet, and are the engines that drive Earth’s biogeochemical cycles,” said Schmidt. “Every day, scientific papers are published on the types of bacteria that live in every imaginable ecosystem. Often, scientists will even go the extra mile to see how patterns of bacterial community composition vary in relation to environmental or host characteristics. However, the underlying reasons for the observed patterns remain unclear. Connecting these patterns to a good understanding of how bacteria interact with each other and their environment will help us to better manage and predict bacterial dynamics in systems that directly affect people, such as human pathogens and wastewater treatment plants." Schmidt’s advisor is Professor Vincent Denef.

"My DDIG research will adapt a trait-based framework developed in plant ecology to microbial ecology to discover the genetic underpinnings of environmental bacterial community compositional changes. I will use a DNA-based inference of genetic traits, such as metabolic pathways or motility, which will help provide a mechanistic and hypothesis-driven examination of the connections between lake bacterial diversity and ecosystem processes. Specifically, my research questions the extent at which the relationship between bacterial diversity and heterotrophic productivity is constrained by the genetic traits that determine community assembly.”

Results of the project will be publicly available and used to create open access online educational tools to aid in teaching computational analyses, scientific reproducibility, and programming literacy. In addition, the workflow will be put together to teach a half day workshop.

The NSF awards DDIGs in selected areas of the biological sciences. These grants provide partial support of doctoral dissertation research to improve the overall quality of research including costs for doctoral candidates to participate in scientific meetings, to conduct research in specialized facilities or field settings, and to expand an existing body of dissertation research.

NSF Graduate Research Fellowship Program

Sanchez's research will expand on her exciting and unexpected discovery during master’s thesis research of antimicrobial properties of algae. McLean is focusing on factors maintaining diversity in host populations during outbreaks of virulent diseases.

GRFP: Katherine McLean

"I use populations of zooplankton and their microparasites to study host-parasite evolution and its impact on epidemiological dynamics,” said McLean. Currently, I’m looking at how a host species remains susceptible to infection despite experiencing strong evolutionary pressure to become resistant. Additionally, I’m studying how parasites interact inside of a host and how those interactions can cause a parasite to evolve to cause more severe disease." Her advisor is Professor Meghan Duffy.

GRFP: Kristel Sanchez

“During my master’s thesis, I found that algae, besides being used as a food source, can also serve as medications to aquatic organisms, specifically Daphnia,” said Sanchez. “I found that when Daphnia consumed toxin-producing strains of cyanobacteria, these diets either protected them from infection or lessened the effects of infection.” These findings have potentially major implications for aquatic ecosystems and humans. “Algae can play a huge role in disease dynamics of aquatic ecosystems and they can also be rich sources of new antimicrobial drugs.” Sanchez’s advisor is Professor Meghan Duffy.

As the oldest graduate fellowship of its kind, the GRFP has a long history of selecting recipients who achieve high levels of success in their future academic and professional careers. The reputation of the GRFP follows recipients and often helps them become life-long leaders that contribute significantly to both scientific innovation and teaching. Since 1952, NSF has funded over 50,000 Graduate Research Fellowships out of more than 500,000 applicants. Currently, 42 Fellows have gone on to become Nobel laureates, including U.S. Secretary of Energy, Steven Chu, Google founder, Sergey Brin and “Freakonomics” co-author, Steven Levitt, and more than 450 have become members of the National Academy of Sciences.