Serological evidence of exposure of Bornean wild carnivores to feline-related viruses at the domestic animal-wildlife interface.

We conducted an exploratory serological survey to evaluate the exposure of Bornean wild carnivores to several viruses common to domestic felids, at interface areas between protected forest and industrial agriculture in the Kinabatangan floodplain (Sabah, Malaysia). Blood samples, collected from wild carnivores (n = 21) and domestic cats (n = 27), were tested for antibodies against feline coronavirus (FCoV), feline panleukopenia virus (FPLV), feline herpesvirus (FHV) and feline calicivirus (FCV), using commercial enzyme-linked immunosorbent assay (ELISA) test kits. Anti-FCoV antibodies were detected in most species, including one flat-headed cat (Prionailurus planiceps, [1/2]), leopard cats (Prionailurus bengalensis, [2/5]), Malay civets (Viverra tangalunga, [2/11]) and domestic cats (Felis catus, [2/27]). Anti-FCV antibodies were present in all domestic cats and one flat-headed cat, while anti-FPLV antibodies were identified in Sunda clouded leopards (Neofelis diardi, [2/2]), domestic cats [12/27] and Malay civets [2/11]. Anti-FHV antibodies were only detected in domestic cats [2/27]. Our findings indicate pathogen transmission risk between domestic and wild carnivore populations at the domestic animal-wildlife interface, emphasizing the concern for wildlife conservation for several endangered wild carnivores living in the area. Special consideration should be given to species that benefit from their association with humans and have the potential to carry pathogens between forest and plantations (e.g., Malay civets and leopard cats). Risk reduction strategies should be incorporated and supported as part of conservation actions in human-dominated landscapes.

First report of foregut microbial community in proboscis monkeys: are diverse forests a reservoir for diverse microbiomes?

Foregut fermentation is well known to occur in a wide range of mammalian species and in a single bird species. Yet, the foregut microbial community of free-ranging, foregut-fermenting monkeys, that is, colobines, has not been investigated so far. We analysed the foregut microbiomes in four free-ranging proboscis monkeys (Nasalis larvatus) from two different tropical habitats with varying plant diversity (mangrove and riverine forests), in an individual from a semi-free-ranging setting with supplemental feeding, and in an individual from captivity, using high-throughput sequencing based on 16S ribosomal RNA genes. We found a decrease in foregut microbial diversity from a diverse natural habitat (riverine forest) to a low diverse natural habitat (mangrove forest), to human-related environments. Of a total of 2700 bacterial operational taxonomic units (OTUs) detected in all environments, only 153 OTUs were shared across all individuals, suggesting that they were not influenced by diet or habitat. These OTUs were dominated by Firmicutes and Proteobacteria. The relative abundance of the habitat-specific microbial communities showed a wide range of differences among living environments, although such bacterial communities appeared to be dominated by Firmicutes and Bacteroidetes, suggesting that those phyla are key to understanding the adaptive strategy in proboscis monkeys living in different habitats.

Nasalization by Nasalis larvatus: Larger noses audiovisually advertise conspecifics in proboscis monkeys.

Male proboscis monkeys have uniquely enlarged noses that are prominent adornments, which may have evolved through their sexually competitive harem group social system. Nevertheless, the ecological roles of the signals encoded by enlarged noses remain unclear. We found significant correlations among nose, body, and testis sizes and a clear link between nose size and number of harem females. Therefore, there is evidence supporting both male-male competition and female choice as causal factors in the evolution of enlarged male noses. We also observed that nasal enlargement systematically modifies the resonance properties of male vocalizations, which probably encode male quality. Our results indicate that the audiovisual contributions of enlarged male noses serve as advertisements to females in their mate selection. This is the first primate research to evaluate the evolutionary processes involved in linking morphology, acoustics, and socioecology with unique masculine characteristics.

Fecal Nutrients Suggest Diets of Higher Fiber Levels in Free-Ranging than in Captive Proboscis Monkeys (Nasalis larvatus).

Understanding the natural diet of species may provide useful information that can contribute to successful captive maintenance. A common problem experienced with captive foregut-fermenting primate (colobine) diets is that they are deficient in fiber and therefore highly digestible. This may contribute to gastrointestinal disorders often observed in zoos. An approach to obtain information relevant for the improvement of diets is to compare the nutrient composition of feces from free-ranging and captive individuals. In theory, fecal material can be considered a proxy for diet intake integrated over a certain period of time. We collected fecal samples from eight free-ranging proboscis monkey (Nasalis larvatus, a highly endangered colobine species) groups from a secondary forest along the Kinabatangan River and four from a mixed mangrove-riverine forest along the Garama River, Sabah, Borneo, Malaysia. We also collected fecal samples from 12 individual captive adult/sub-adult proboscis monkeys from three different zoos. We confirmed that feces from free-ranging monkeys contained more fiber and less metabolic fecal nitrogen than those from captive specimens, indicating a less digestible diet in the wild. Modifying the diets of captive colobines to include more fiber, comparable to those of free-ranging ones, may contribute to their health and survival.