Grantee: Amanda Koltz

Institutions: University of Texas at Austin, United States

Grant amount: $167,237

Grant type: Challenge grant

Focal species: White-footed mouse (Peromyscus leucopus) and their helminth parasites

Conservation status: Least concern

Disciplines: Infectious disease, animal welfare science, animal behavior, physiology, community ecology

Research location: United States

Project summary

Parasite-mediated changes in host traits can have far-reaching ecological effects. Even sublethal infections affect hosts by increasing energetic costs and altering behavior, immunity, and physiology. Yet while many studies have investigated parasite effects on specific host traits, our understanding of how parasites influence overall individual welfare is limited, especially for wild animals. For example, parasites can drive changes in host diet and habitat use that reduce parasite exposure but not necessarily improve other metrics of host welfare. A holistic approach that captures different types of individual-level responses to parasitism is needed to advance our overall understanding of sublethal infections on host welfare. We propose to investigate how parasite burden is associated with individual-level host welfare using white-footed deer mice (Peromyscus leucopus) and their helminth parasites as a model system. Specifically, by experimentally removing gastrointestinal helminth parasites from P. leucopus, we will test how variation in parasite burden influences individual host body condition, diet and nutrition, microbiome, stress physiology, anxiety-like behavior, and exploratory behavior in forested ecosystems. P. leucopus has become the dominant small mammal species over the last 40 years in the northern Great Lakes region. It experiences sublethal infection by a range of helminth parasites and is a reservoir for several zoonotic pathogens, making its host-parasite dynamics highly relevant to the health of humans and other wildlife. By examining how infection levels relate to the diet, body functions, and behavior of P. leucopus, this study will advance our understanding of how non-lethal parasitic infections affect the welfare of an extremely widespread wild animal species.

Why we funded this project

We are excited to fund a study on wild mice, a highly numerous and neglected group, and especially one with such a welfare-friendly experimental approach — curing parasitic infections rather than causing them. The project also uses a holistic suite of physiological and behavioral indicators that should allow the researchers to disentangle overall welfare from narrow, mechanistic impacts of infection on the health and nutrition domains.