research team mentor

Principal Investigator
Rachel Penczykowski, PhD

Assistant Professor of Biology, Washington University in St. Louis
Research website:

Research focus for summer 2019

Our research group seeks to understand how environmental variation affects the ecology and evolution of infectious diseases, and how diseases can impact the ecosystems in which they occur. We use common weedy plants (Plantago species) and their fungal pathogens (powdery mildews) as a model system for investigating environment-disease interactions.

Important questions we ask include:

  • How does large-scale latitudinal variation in winter climate drive variation in the prevalence and diversity of fungal parasites?

  • How does variation in microhabitat (e.g., shade) and land management practices (e.g., mowing) affect plant demography and plant-pathogen interactions?

  • How do parasites affect flows of energy and nutrients through food webs and alter ecosystem processes?

This summer, our team will focus on two projects at Tyson Research Center:

  • Microhabitat, land management, and disease: We will conduct field experiments in which we manipulate environmental variables and mowing frequency in patches of wild Plantago, and quantify effects on plant demography and powdery mildew epidemiology. In addition, we will conduct an annual census of permanent research plots as part of the PlantPopNet network. This global network uses replicated plots of Plantago lanceolata to study fundamental questions about population ecology, including disease ecology.

  • Plant pathogens in food webs: We will carry out two experiments to study how powdery mildew alters the flow of energy and nutrients through simplified food webs consisting of soil communities, plants, powdery mildew, and a specialist herbivore. The first experiment will occur in microcosms (small caged pots) in a hoop house, and the second experiment will involve mesocosms (large caged plots) in a research garden.


Members of our team will work together to carry out multiple projects investigating environment-disease interactions, and we seek a group of students with diverse backgrounds, interests, and personalities. Students on our team can expect to develop a suite of skills in areas of field and laboratory research, data analysis, and teamwork, and will receive training and mentoring including in the following areas:

  • Field experiments and surveys

    • Identification of common weedy plants and their fungal pathogens

    • Manipulation and measurement of key environmental variables (e.g., temperature, humidity, and light levels)

    • Measurement of plant traits including leaf size, flower development stage, and severity of damage from disease and herbivory

  • Microcosm and mesocosm food web experiments

    • Methods for planting, maintaining, and harvesting Plantago

    • Methods for working with caterpillars

    • Methods for inoculating with powdery mildew

    • Collection and analysis of samples for biomass and nutrient content

  • Data collection, management, and analysis

    • Best practices for documentation in field and lab notebooks and datasheets

    • Best practices for data entry and curation in Excel

    • Data analysis using R

  • Teamwork and communication skills

research conditions

Students can expect to be in the field 75% of the time and lab 25% of the time. Indoor lab activities will include: (1) identifying plant pathogens under a dissecting microscope; (2) processing plant, soil, and herbivore samples for biomass and nutrient analyses; and (3) data entry and analysis.

Field conditions will be primarily in short vegetation in open habitats. Students will need to take precautions against ticks, mosquitoes, and sunburn.

Team structure and opportunities for independent research

Our anticipated team size will be 10 people, including two primary research mentors (Principal Investigator: Rachel Penczykowski, Technician and Lab Manager: Carrie Goodson), four undergraduate research fellows, and four high school research fellows (two in June and two in July). We will have weekly team meetings.

Our team will work collaboratively on all projects, with supervision by the research mentors. Undergraduate students will also have the opportunity to be near-peer mentors for high school fellows. We encourage motivated students to pursue independent research projects. These can include: (1) data collection, data analyses, and/or data syntheses that lead to a research poster presentation at the Washington University Undergraduate Research Symposium; (2) independent research for course credit (BIOL 200 or BIOL 500) in the fall or spring semesters; and (3) senior honors theses that lead to research presentations at professional conferences and/or peer-reviewed publications. Students interested in senior honors theses should contact Rachel Penczykowski prior to the start of the field season.