Global variation in the ecology of mammalian parasites

In collaboration with Charlie Nunn (Max Planck Institute for Evolutionary Anthropology), Vanessa Ezenwa, and researchers at 8 other institutions, we are building large-scale databases of parasites reported from free-living primates, carnivores, and artiodactyls (hoofed mammals) to explore broad patterns of host-parasite ecology and evolution. Collectively, our databases include tens of thousands of lines of data, reflecting published reports of viruses, bacteria, fungi, protozoa, helminths and arthropods recorded in free-living mammal populations.

You can learn more about these projects, our collaborators and comprehensive data sets by visiting our project webpage, the Global Mammal Parasite Database.

Some questions we have examined with these data sets include:

  1. What host characteristics, including life history, sociality, and habitat use, best predict patterns of parasite species richness in primates?
  2. Does primate disease risk increase closer to the tropics, and how does this relate to parasite transmission strategy?
  3. What are the patterns of host specificity and transmission mode among parasites of wild primates? Are most parasites host specific? Does transmission mode and parasite taxonomy affect the level of host specificity?

More recently, we examined the role of parasites in mammalian extinctions using these comparative datasets to investigate the following questions:

  1. Do threatened mammals have fewer parasites than non-threatened taxa, and what types of parasites occur in populations of threatened mammals?
  2. What parasites cause mammalian extinction risk? Are these threatening parasites likely to have a wide host range that includes domesticated animals? What hosts are likely to be threatened to extinction by parasites? Do specific taxonomic groups or geographically locations predispose host to parasite risk?
  3. What factors determine parasite host range? Are sympatric host species more likely to share parasites? Are two species that do share parasites more likely to have a recent diversification time?

Figure 1. Parasite species richness in primates (after controlling for sampling effort) in relation to social group size. Points represents different primate host species.

Figure 2. Parasite species richness in threatened and non-threatened primates, where threat status was based on IUCN red list categories. Data are shown for parasites categorized as generalists (blue) and specialists (red).