Pathogens and parasites are a major component of biological diversity, and have important impacts on natural populations. A central question in host-parasite ecology concerns what features of host behavior, life history, and environment best explain the diversity and evolution of infectious diseases. Significant theoretical progress has advanced our understanding of factors that influence infectious disease dynamics within populations, yet relatively few studies have analyzed ecological variables that underlie observed variation in pathogen diversity and characteristics. This project will examine patterns of parasite diversity across three mammalian orders to explicitly test predictions derived from both epidemiological models and island biogeography theory. Major questions this project will address include (1) What are the key ecological variables that determine variation in the types and diversity of parasites in wild mammal populations? (2) How do parasite transmission mode and the degree of specificity depend on host ecology? (3) Does evolutionary diversification of hosts correlate with patterns of parasite species richness? (4) Does knowledge of parasite diversity have important implications for wildlife conservation? Establishing a large database on the pathogens and parasites infecting wild mammals is critical to conducting comprehensive analyses and represents a major goal of this project. The investigators have recently assembled a large database on the pathogens and parasites of primates and will extend this effort to two other well-studied groups - carnivores and ungulates. These databases capture (i) ecological, behavioral and life history traits relevant to theoretical models of disease spread, (ii) records of parasites and pathogens recovered from wild populations, (iii) data on parasite transmission mode and degree of host specificity, and (iv) phylogenetic information on the hosts. Database development requires an immense effort and following this study all data will be made freely available over the World Wide Web so that other scientists can access the fruits of this labor. Understanding factors that underlie parasite diversity and characteristics is vital to managing vulnerable wildlife populations and mitigating threats to human health. This study extends the scope of previous host-parasite comparative work by examining a rich diversity of both micro- and macroparasites, including information on parasite characteristics, and by assessing phylogenetic information involving tree topology, branch lengths and rates of host diversification. Analytical comparative methods will control for sampling effort, test multiple variables simultaneously, and will assess whether host and parasite traits are correlated with phylogeny. A synthetic approach that links ecology, parasitology, epidemiology, and phylogenetic comparative methods is crucial for developing a broad conceptual framework to explain parasite diversity and characteristics in relation to host features. To advance these goals, the investigators will organize three annual workshops composed of experts from each of these disciplines to refine predictions for comparative research, explore methods for examining ecological and evolutionary interactions in host-parasite assemblages, and chart future directions for both theoretical and empirical work.
