Interaction between Old World fruit bats and humans: From large scale ecosystem services to zoonotic diseases

The Old World tropical and subtropical frugivorous bat genus Rousettus (Pteropodidae) contains species with broad distributions, as well as those occurring in restricted geographical areas, particularly islands. Herein we review the role of Rousettus as a keystone species from a global "One Health" approach and related to ecosystem functioning, zoonotic disease and public health. Rousettus are efficient at dispersing seeds and pollinating flowers; their role in forest regeneration is related to their ability to fly considerable distances during nightly foraging bouts and their relatively small body size, which allows them to access fruits in forested areas with closed vegetation. Rousettus are also reservoirs for various groups of pathogens (viruses, bacteria, fungi, protozoa), which, by definition, are infectious agents causing disease. The study of day roosts of different species of Rousettus and the successful establishment of captive breeding colonies have provided important details related to the infection dynamics of their associated pathogens. Large-scale conversion of forested areas into agricultural landscapes has increased contact between humans and Rousettus, therefore augmenting the chances of infectious agent spillover. Many crucial scientific details are still lacking related to members of this genus, which have direct bearing on the prevention of emerging disease outbreaks, as well as the conservation of these bats. The public should be better informed on the capacity of fruit bats as keystone species for large scale forest regeneration and in spreading pathogens. Precise details on the transmission of zoonotic diseases of public health importance associated with Rousettus should be given high priority.

Phylogeny and biogeography of western Indian Ocean Rousettus (Chiroptera: Pteropodidae)

We examined patterns of genetic variation in Rousettus madagascariensis from Madagascar and R. obliviosus from the Comoros (Grande Comore, Anjouan, and Mohéli). Genetic distances among individuals on the basis of 1,130 base pairs of the mitochondrial cytochrome b (Cytb) locus were estimated from specimens collected from 17 sites on Madagascar, 3 sites on Grande Comore, 3 sites on Anjouan, and 2 sites on Mohéli. We observed little variation in Madagascar and nearshore island samples (maximum 1.1%) and interisland Comoros samples (maximum 1.8%). In contrast, pairwise distances between different sampled sites on Madagascar and the Comoros varied from 8.5% to 13.2%. For 131 Malagasy animals, 69 unique haplotypes were recovered with 86 variable sites, and for 44 Comorian individuals, 17 unique haplotypes were found with 30 variable sites. No haplotype was shared between Madagascar and the Comoros, adding to previous morphological evidence that these 2 populations should be considered separate species. Cytb data showed that Rousettus populations of Madagascar (including nearshore islands) and the Comoros are respectively monophyletic and display no geographic structure in haplotype diversity, and that R. madagascariensis and R. obliviosus are strongly supported as sister to each other relative to other Rousettus species. Genotypic data from 6 microsatellite loci confirm lack of geographic structure in either of the 2 species. In pairwise tests of population differentiation, the only significant values were between samples from the Comoro Islands and Madagascar (including nearshore islands). Estimates of current and historical demographic parameters support population expansion in both the Comoros and Madagascar. These data suggest a more recent and rapid demographic expansion in Madagascar in comparison with greater population stability on the Comoros. On the basis of available evidence, open-water crossings approaching 300 km seem rarely traversed by Rousettus, and, if successful, can result in genetic isolation and subsequent differentiation.

Molecular phylogenetic analysis of nycteribiid and streblid bat flies (Diptera: Brachycera, Calyptratae): implications for host associations and phylogeographic origins

Bat flies are a small but diverse group of highly specialized ectoparasitic, obligatory bloodsucking Diptera. For the first time, the phylogenetic relationships of 26 species and five subfamilies were investigated using four genes (18S rDNA, 16S rDNA, COII, and cytB) under three optimality criteria (maximum parsimony (MP), maximum likelihood (ML), and Bayesian inference). Tree topology tests of previous hypotheses were conducted under likelihood (Shimodaira-Hasegawa test). Major findings include the non-monophyly of the Streblidae and the recovery of an Old World- and a New World-Clade of bat flies. These data ambiguously resolve basal relationships between Hippoboscidae, Glossinidae, and bat flies. Recovered phylogenies resulted in either monophyly (Bayesian approach) or paraphyly (MP/ML topologies) of the bat flies, thus obscuring the potential number of possible associations with bats throughout the history of this group. Dispersal-vicariance analysis suggested the Neotropical region as the possible ancestral distribution area of the New World Streblidae and the Oriental region for the Old World bat flies. The genes examined show conflicting support across the nodes of the tree, particularly in the basal positions. Additionally, there is poor character support among all genes for the nodes associated with early hippoboscoid diversification. This results in extremely short basal branches, adding support to the idea of a rapid radiation among the four major groups of Hippoboscoidea.