Research

My research focuses on relationships of animals with their natural enemies, especially parasites and predators, in the context of environmental change. I am currently focused on two questions: How does environmental change in streams affect parasitism? And, how do parasites affect other ecological interactions of their hosts, such as food consumption or vulnerability to predation?

ENVIRONMENTAL DRIVERS OF DISEASE

A multitude of abiotic factors can affect hosts, parasites or the outcome of their encounters.

We have evidence from infected mayflies (in high-altitude streams near the Rocky Mt. Biological Laboratory) that warming temperatures could decrease encounters of infectious parasites with their susceptible hosts by having different effects on the developmental timing of hosts and parasites.

With undergraduate collaborator Jasmine Hamilton, we also found that heavy metal pollution interacts with parasitism to change host behavior and increase vulnerability to predation.

Hydrology is the principal force structuring stream habitats and it shapes the life histories and distributions of organisms as well. Human activity has profound direct and indirect effects on natural flow regimes. With collaborators in Winsor Lowe’s lab at the University of Montana I am looking at effects of stream flow variation on host-parasite interactions.

Ecological consequences of disease

The effects parasites have on their hosts’ condition and behavior can propagate into other key biotic interactions, such as food web relationships and nutrient transfer. In the mayfly system we discovered that parasites decrease the exposure and predation of their hosts to benefit their own survival in risky environments.

Further, predation risk causes parasites to have more virulent effects on their hosts by depleting host resources faster. Combining this with our finding that parasites can decrease their host’s dispersal capacity, I hope to test the hypothesis that predators indirectly decrease parasite dispersal and depress gene flow.

In a collaboration led by Andrew Sanders and Brad Taylor at North Carolina State University, we learned that aquatic parasites can have diverse, context-specific effects on their hosts’ nutrient recycling, which creates the potential for higher order impacts on ecosystem function.

Beyond the science of parasites and predators, I am interested in how people perceive the creepy, crawly or “disgusting” elements of biodiversity, and I try to find creative ways to communicate about nature's unseemly side.