Bat Distribution Size or Shape as Determinant of Viral Richness in African Bats

Maganga, Gaël D.; Bourgarel, Mathieu; Vallo, Peter; Dallo, Thierno D.; Ngoagouni, Carine; Drexler, Jan Felix; Drosten, Christian; Nakouné, Emmanuel R.; Leroy, Eric M.; Morand, Serge

This is the first comparative analysis investigating the effect of distribution shape, i.e. geographical range fragmentation or edge range density, on viral richness in bats. Our first hypothesis was that bats living in caves in sympatry with other species with increased promiscuity and high population density of susceptible individuals, would generate opportunities for cross-species transmission of viruses and their rapid spread. However, our study does not support this hypothesis. Our results showed a significant influence of host body weight, distribution size and shape on viral richness; viral richness increases with larger distribution areas and fragmentation of bat distribution, according to the measure of their distribution shape. Before discussing this correlation, the difference between habitat fragmentation and habitat loss should be considered since Fahrig [17] suggested that the two processes are independent. An ecological explanation of the correlation between viral richness and distribution could be interpreted in the light of the historical biogeography of African bats, which falls within the domain of phylogeny and phylogeographic studies [31] . Range distributions and shapes are the product of speciation, extinction and historical displacements [18] . The accumulation of Table 6 . Comparison of models used to test the effects of several independent variables (weight, size and shape of distribution, migration, roosting and sample size) on viral richness of bats (using the independent contrasts), using phylogenetic regression (Independent contrasts) or non-phylogenetic regression (raw values).