Main Research Themes
Host Movement and Infection Risk: My focal research investigates how individual patterns of movement affect disease risk. Humans and wildlife embark on daily travel and undergo larger-scale seasonal migrations, all of which create travel networks that determine how far and how fast their parasites spread. Parasite spread not only poses clear public health implications but can also have a wide range of ecological consequences; parasites affect an individual’s behaviour and interactions, alter the structure and resilience of ecological communities, and change how energy flows through food webs. My research collects high-resolution data on individual movements to test the factors driving variation in movement traits. Through field surveys and modelling, I assess how individual variation of mobility scale up to influence landscape-scale patterns of infection.
This work has contributed new theory for predicting how host movements affect disease dynamics (see figure, above) , and I have empirically studied this topic with amphibians and the devastating fungal pathogen Batrachochytrium dendrobatidis (Bd) [2–5]. Bd is the causal agent of the disease chytridiomycosis, a major culprit in the amphibian declines and reductions in global biodiversity. My research revealed that toads recover from Bd infections when migrating from aquatic breeding ponds to terrestrial shelters  and that newts behaviourally respond to Bd infections by moving to habitats that inhibit Bd survival . Together, these findings emphasize that, in addition to spreading parasites, movement can protect hosts from them. More broadly, this work demonstrated the importance of habitats and behaviours associated with host activity for infection risk, while providing new insights for disease mitigation strategies .
Multi-trophic Disease Dynamics: The real ecosystems in which parasites thrive contain multiple consumers that feed on the same organisms. For example, parasites such as bacteria, viruses, and fungi often co-infect and interact within shared hosts. Predators are also key members of most ecosystems that can feed on parasites or their hosts. I am establishing a research program that investigates these more complex, yet more realistic, interactions between parasites and predators. Specifically, my research is asking what effects predators have on infection and co-infection dynamics, and how host movements mediate those effects. For example, my recent experiments tested how newt movement in different habitats mediate interactions between aquatic invertebrates that eat Bd spores. Undergraduate and postgraduate student research under my supervision is clarifying interactions between aquatic grazers and Bd, as well as newt-grazer interactions, which can be combined to develop theory for spatial disease dynamics in multi-trophic communities. I am also developing theory for the non-lethal effects that predators and parasites impose on the organisms on which they feed . A preliminary synthesis of the data indicates that predators elicit strong responses before attacking prey, while parasites elicit responses only after infecting and beginning to feed on animals (See figure, below), suggesting differences in the timing of responses that may need accounting for when estimating their impact on infection dynamics. I am applying these insights to explore how the combined threats of predation and parasitism influence individual patterns of movement, and more broadly, disease risk.