Outbreaks of disease continue to increase in wild populations, and understanding this increase has become a major environmental challenge. A popular explanation is that loss of biodiversity, and particularly of species that are resistant to disease, encourages disease epidemics. Thus, enhancement and preservation of species diversity might reduce disease and associated negative effects on host populations. This project combines new mathematical models with experiments to challenge this explanation in a food web/community context, using Daphnia (an aquatic invertebrate) and a fungal pathogen, to explore how the dilution effect of multiple pathogen hosts plays itself out in the face of ecological (interspecific competition) and evolutionary dynamics. The PI's propose that key traits determining transmission also affect interactions with other community members, exploitative competitors and their shared prey in this case, which may alter the details of host-pathogen dynamics, particularly the dilution effect. Models and experiments together will determine whether competition among hosts also influences the spread of disease, whether nutritional value of the food for which hosts compete influences susceptibility to disease, and whether rapid adaptation of hosts to disease can counteract the loss of biodiversity, potentially reducing disease outbreaks. An interdisciplinary team of researchers will tackle these issues using common freshwater organisms that are infected by a virulent pathogen. The Daphnia-fungus system is ideal for asking elegant theoretical questions, and the proposed ambitious experiments will generate empirical data to test the theory.
This multi-disciplinary project will produce new insights into a provocative option for disease control. This project will also enhance training opportunities for students and postdoctoral researchers, with particular focus on members of underrepresented groups and undergraduates working with mathematics and biology. Additionally, the investigators will work through non-governmental organizations, high schools, a children's museum, and a program for middle school girls to disseminate results and train future scientists with hands-on projects.
