Association of human disturbance and gastrointestinal parasite infection of yellow baboons in western Tanzania

Human disturbance is an ongoing threat to many wildlife species, manifesting as habitat destruction, resource overuse, or increased disease exposure, among others. With increasing human: non-human primate (NHP) encounters, NHPs are increasingly susceptible to human-introduced diseases, including those with parasitic origins. As such, epidemiology of parasitic disease is becoming an important consideration for NHP conservation strategies. To investigate the relationship between parasite infections and human disturbance we studied yellow baboons (Papio cynocephalus) living outside of national park boundaries in western Tanzania, collecting 135 fresh faecal samples from nine troops occupying areas with varying levels of human disturbance. We fixed all samples in 10% formalin and later evaluated parasite prevalence and abundance (of isotrichid ciliates and Strongylida). We identified seven protozoan and four helminth taxa. Taxa showed varied relationships with human disturbance, baboon troop size and host age. In four taxa, we found a positive association between prevalence and troop size. We also report a trend towards higher parasite prevalence of two taxa in less disturbed areas. To the contrary, high levels of human disturbance predicted increased abundance of isotrichid ciliates, although no relationship was found between disturbance and Strongylida abundance. Our results provide mixed evidence that human disturbance is associated with NHP parasite infections, highlighting the need to consider monitoring parasite infections when developing NHP conservation strategies.

Better baboon break-ups: collective decision theory of complex social network fissions

Many social groups are made up of complex social networks in which each individual associates with a distinct subset of its groupmates. If social groups become larger over time, competition often leads to a permanent group fission. During such fissions, complex social networks present a collective decision problem and a multidimensional optimization problem: it is advantageous for each individual to remain with their closest allies after a fission, but impossible for every individual to do so. Here, we develop computational algorithms designed to simulate group fissions in a network-theoretic framework. We focus on three fission algorithms (democracy, community and despotism) that fall on a spectrum from a democratic to a dictatorial collective decision. We parameterize our social networks with data from wild baboons ( Papio cynocephalus ) and compare our simulated fissions with actual baboon fission events. We find that the democracy and community algorithms (egalitarian decisions where each individual influences the outcome) better maintain social networks during simulated fissions than despotic decisions (driven primarily by a single individual). We also find that egalitarian decisions are better at predicting the observed individual-level outcomes of observed fissions, although the observed fissions often disturbed their social networks more than the simulated egalitarian fissions.

Investigation of the Behavioural Response of a Colony of Group-Housed Hamadryas Baboons (Papio Cynocephalus Hamadryas) to Relocation to a More Naturalistic Enclosure

<p>As part of Wellington Zoo’s current management philosophy to reduce the number of species and increase enclosure size, quality and appropriateness for those remaining animals, the zoo’s colony of hamadryas baboons (Papio cynocephalus hamadryas) was relocated within the zoo to a purpose-designed and more naturalistic exhibit. The primary objective of this investigation was to determine group and individual responses of five of these baboons to their new enclosure. In so doing, this investigation was intended to address the shortage of quantitative, species-specific information on environmental enrichment for Papio baboons (Kessel and Brent 1996). The data collection method used in this investigation consisted of fifteen-minute focal sampling of each of the five focal animals in the two months before and the month following the colony’s relocation. For the purposes of this investigation, these focal samples were initially analysed together, prior to each focal animal being considered independently. Analysis of data extracted from these focal samples included consideration of: • The overall occurrence of individual behaviours between the former and new enclosures; • Additions to the animals’ behavioural repertoires upon relocation; and, • Time the animals spent alone and interacting socially. Upon the colony’s relocation, changes in the combined focal animals’ behaviour were anticipated as a result of greater space, areas of privacy, and increased environmental variation. Focal sampling revealed increasingly naturalistic behaviours, including a reduction in vacuum and vestigial behaviours, and an increase in speciestypical behaviour. Results also indicated that the combined focal animals experienced unexpectedly low levels of “agonistic” (i.e. aggressive) behaviour in both enclosures. However, there was a reduction in some associated behaviours upon the colony’s relocation. This included a decline in male rivalry over females. Differences in the responses of individual focal animals to relocation were also anticipated. Of particular interest were results indicating an increasing similarity of individual roles within one-male units to those of free-ranging hamadryas baboons. These roles were associated with both age and sex. This study raises implications for improving the current management of the Wellington Zoo colony and other captive hamadryas baboon colonies. These include emphasising the importance of appropriate husbandry and feeding schedules. It also raises implications for the future management of other captive Papio baboon colonies in terms of enclosure redesign. These include the benefit of incorporating naturally occurring environmental factors, such as natural leaf litter. This study is also of value from a management perspective as a baseline for future investigations. Such investigations could include long-term monitoring of this colony’s use of environmental enrichment in the new enclosure and consideration of the animals’ behaviour as the colony is encouraged to expand.</p>

Investigation of the Behavioural Response of a Colony of Group-Housed Hamadryas Baboons (Papio Cynocephalus Hamadryas) to Relocation to a More Naturalistic Enclosure

<p>As part of Wellington Zoo’s current management philosophy to reduce the number of species and increase enclosure size, quality and appropriateness for those remaining animals, the zoo’s colony of hamadryas baboons (Papio cynocephalus hamadryas) was relocated within the zoo to a purpose-designed and more naturalistic exhibit. The primary objective of this investigation was to determine group and individual responses of five of these baboons to their new enclosure. In so doing, this investigation was intended to address the shortage of quantitative, species-specific information on environmental enrichment for Papio baboons (Kessel and Brent 1996). The data collection method used in this investigation consisted of fifteen-minute focal sampling of each of the five focal animals in the two months before and the month following the colony’s relocation. For the purposes of this investigation, these focal samples were initially analysed together, prior to each focal animal being considered independently. Analysis of data extracted from these focal samples included consideration of: • The overall occurrence of individual behaviours between the former and new enclosures; • Additions to the animals’ behavioural repertoires upon relocation; and, • Time the animals spent alone and interacting socially. Upon the colony’s relocation, changes in the combined focal animals’ behaviour were anticipated as a result of greater space, areas of privacy, and increased environmental variation. Focal sampling revealed increasingly naturalistic behaviours, including a reduction in vacuum and vestigial behaviours, and an increase in speciestypical behaviour. Results also indicated that the combined focal animals experienced unexpectedly low levels of “agonistic” (i.e. aggressive) behaviour in both enclosures. However, there was a reduction in some associated behaviours upon the colony’s relocation. This included a decline in male rivalry over females. Differences in the responses of individual focal animals to relocation were also anticipated. Of particular interest were results indicating an increasing similarity of individual roles within one-male units to those of free-ranging hamadryas baboons. These roles were associated with both age and sex. This study raises implications for improving the current management of the Wellington Zoo colony and other captive hamadryas baboon colonies. These include emphasising the importance of appropriate husbandry and feeding schedules. It also raises implications for the future management of other captive Papio baboon colonies in terms of enclosure redesign. These include the benefit of incorporating naturally occurring environmental factors, such as natural leaf litter. This study is also of value from a management perspective as a baseline for future investigations. Such investigations could include long-term monitoring of this colony’s use of environmental enrichment in the new enclosure and consideration of the animals’ behaviour as the colony is encouraged to expand.</p>

Selection against admixture and gene regulatory divergence in a long-term primate field study

Admixture has profoundly influenced evolution across the tree of life, including in humans and other primates. However, we have limited insight into the genetic and phenotypic consequences of admixture in primates, especially during its key early stages. Here, we address this gap by combining 50 years of field observations with population and functional genomic data from yellow (Papio cynocephalus) and anubis (P. anubis) baboons in Kenya, in a longitudinally studied population that has experienced both historical and recent admixture. We use whole-genome sequencing to characterize the extent of the hybrid zone, estimate local ancestry for 442 known individuals, and predict the landscape of introgression across the genome. Despite no major fitness costs to hybrids, we identify signatures of selection against introgression that are strikingly similar to those described for archaic hominins. These signatures are strongest near loci with large ancestry effects on gene expression, supporting the importance of gene regulation in primate evolution and the idea that selection targeted large regulatory effects following archaic hominin admixture. Our results show that genomic data and field observations of hybrids are important and mutually informative. They therefore demonstrate the value of other primates as living models for phenomena that we cannot observe in our own lineage.

Contemporary Distribution, Estimated Age, and Prehistoric Migrations of Old World Monkey Retroviruses

Old World monkeys (OWM), simians inhabiting Africa and Asia, are currently affected by at least four infectious retroviruses, namely, simian foamy virus (SFV), simian immunodeficiency virus (SIV), simian T-lymphotropic virus (STLV), and simian type D retrovirus (SRV). OWM also show chromosomal evidence of having been infected in the past with four more retroviral species, baboon endogenous virus (BaEV), Papio cynocephalus endogenous virus (PcEV), simian endogenous retrovirus (SERV), and Rhesus endogenous retrovirus-K (RhERV-K/SERV-K1). For some of the viruses, transmission to other primates still occurs, resulting, for instance, in the HIV pandemic. Retroviruses are intimately connected with their host as they are normally spread by close contact. In this review, an attempt to reconstruct the distribution and history of OWM retroviruses will be made. A literature overview of the species infected by any of the eight retroviruses as well as an age estimation of the pathogens will be given. In addition, primate genomes from databases have been re-analyzed for the presence of endogenous retrovirus integrations. Results suggest that some of the oldest retroviruses, SERV and PcEV, have travelled with their hosts to Asia during the Miocene, when a higher global temperature allowed simian expansions. In contrast, younger viruses, such as SIV and SRV, probably due to the lack of a primate continuum between the continents in later times, have been restricted to Africa and Asia, respectively.

Effects of early life adversity on maternal effort and glucocorticoids in wild olive baboons

Adverse experiences during early life exert important effects on development, health, reproduction, and social bonds, with consequences often persisting across generations. A mother's early life experiences can impact her offspring's development through a number of pathways, such as maternal care, physiological signaling through glucocorticoids, or even intergenerational effects like epigenetic inheritance. Early life adversity in female yellow baboons (Papio cynocephalus) predicts elevated glucocorticoids, reduced sociality, shortened lifespan, and higher offspring mortality. If baboon mothers with more early life adversity, experience poorer condition and struggle to provide for their offspring, this could contribute to the persisting transgenerational effects of adversity. Here, we examined the effects of mothers' early life adversity on their maternal effort, physiology, and offspring survivability in a population of olive baboons, Papio anubis. Mothers who experienced more adversity in their own early development exerted greater maternal effort (i.e., spent more time nursing and carrying) and had higher glucocorticoid metabolites than mothers with less early life adversity. Offspring of mothers with more early life adversity had reduced survivability compared to offspring of mothers with less early life adversity. There was no evidence that high maternal social rank buffered against the effects of early life adversity. Our data suggest early life experiences can have lasting consequences on maternal effort and physiology, which may function as proximate mechanisms for intergenerational effects of maternal experience.

Genetic ancestry predicts male-female affiliation in a natural baboon hybrid zone

ABSTRACTOpposite-sex social relationships are important predictors of fitness in many animals, including several group-living mammals. Consequently, understanding sources of variance in the tendency to form opposite-sex relationships is important for understanding social evolution. Genetic contributions are of particular interest due to their importance in long-term evolutionary change, but little is known about genetic effects on male-female relationships in social mammals, especially outside of the mating context. Here, we investigate the effects of genetic ancestry on male-female affiliative behavior in a hybrid zone between the yellow baboon (Papio cynocephalus) and the anubis baboon (P. anubis), in a population in which male-female social bonds are known predictors of lifespan. We place our analysis within the context of other social and demographic predictors of affiliative behavior in baboons. Genetic ancestry was the most consistent predictor of opposite-sex affiliative behavior we observed, with the exception of strong effects of dominance rank. Our results show that increased anubis genetic ancestry is associated with subtly, but significantly higher rates of opposite-sex affiliative behavior, in both males and females. Additionally, pairs of anubis-like males and anubis-like females were the most likely to socially affiliate, resulting in moderate assortativity in grooming and proximity behavior as a function of genetic ancestry. Our findings indicate that opposite-sex affiliative behavior partially diverged during baboon evolution to differentiate yellow and anubis baboons, despite overall similarities in their social structures and mating systems. Further, they suggest that affiliative behavior may simultaneously promote and constrain baboon admixture, through additive and assortative effects of ancestry, respectively.HIGHLIGHTSOpposite-sex social relationships can have important fitness consequences.In hybrid baboons, genetic ancestry predicted male-female affiliative behavior.Both an individual’s genetic ancestry and that of its social partner mattered.Male-female affiliation was assortative with respect to genetic ancestry.Dominance rank and group demography also influenced male-female social affiliation.

Global view on virus infection in non-human primates and implication for public health and wildlife conservation

The pandemic outbreak and rapid worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is not only a threat for humans, but potentially also for many animals. Research has revealed that SARS-CoV-2 and other coronaviruses have been transmitted from animals to humans and vice versa, and across animal species, and hence, attracted public attention concerning host-virus interactions and transmission ways. Non-human primates (NHPs), as our evolutionary closest relatives, are susceptible to human viruses, and a number of pathogens are known to circulate between humans and NHPs. Here we generated global statistics of virus infection in NHPs (VI-NHPs). In total, 121 NHP species from 14 families have been reported to be infected by 139 DNA and RNA viruses from 23 virus families; 74.8 percent of viruses in NHPs have also been found in humans, indicative of the high potential for cross species transmission of these viruses. The top ten NHP species with high centrality in the NHP-virus network are two apes (Pan troglodytes, Pongo pygmaeus), seven Old World monkeys (Macaca mulatta, M. fascicularis, Papio cynocephalus, Lophocebus albigena, Chlorocebus aethiops, Cercopithecus ascanius, C. nictitans) and a lemur (Propithecus diadema). Besides apes, there is a high risk of virus circulation between humans and Old World monkeys, given the wide distribution of many Old World monkey species and their frequent contact with humans. We suggest epidemiological investigations in NHPs, specifically in Old World monkeys with close contact to humans, and other effective measures to prevent this potential circular transmission.