Correlates of viral richness in bats (order Chiroptera)

Abstract

Historic and contemporary host ecology and evolutionary dynamics have profound impacts on viral diversity, virulence, and associated disease emergence. Bats have been recognized as reservoirs for several emerging viral pathogens, and are unique among mammals in their vagility, potential for long-distance dispersal, and often very large, colonial populations. We investigate the relative influences of host ecology and population genetic structure for predictions of viral richness in relevant reservoir species. We test the hypothesis that host geographic range area, distribution, population genetic structure, migratory behavior, International Union for Conservation of Nature and Natural Resources (IUCN) threat status, body mass, and colony size, are associated with known viral richness in bats. We analyze host traits and viral richness in a generalized linear regression model framework, and include a correction for sampling effort and phylogeny. We find evidence that sampling effort, IUCN status, and population genetic structure correlate with observed viral species richness in bats, and that these associations are independent of phylogeny. This study is an important first step in understanding the mechanisms that promote viral richness in reservoir species, and may aid in predicting the emergence of viral zoonoses from bats.

Figure 1

a The phylogeny extracted from the mammalian supertree (with branch lengths) for 29 of 32 taxa (Bininda-Emonds et al., 2007). b The phylogeny in which three additional taxa were added (highlighted in bold).

Figure 2

The number of viruses associated with bats, for species with known population structure estimates and at least one viral association (n = 33).

Figure 3

The three significant predictor variables from the best generalized linear model. Panels show the relationship between IUCN threat status (a), global F_ST (b), sampling effort (c), and viral richness across bat species (n = 32). Each data point represents one bat species in the linear regressions. NT/VU, near-threatened/vulnerable; LC, least concern.