172 research outputs found
Neopterin Levels in Bonobos Vary Seasonally and Reflect Symptomatic Respiratory Infections
No full textAs environmental changes exacerbate the threat coming from infectious diseases in wild mammal species, monitoring their health and gaining a better understanding of the immune functioning at the species level have become critically important. Neopterin is a biomarker of cell-mediated immune responses to intracellular infections. We investigated the variation of urinary neopterin (uNeo) levels of wild, habituated bonobos (Pan paniscus) in relation to individual and environmental factors. We used 309 urine samples collected between 2010 and 2018 at the LuiKotale field site, DRC. Based on current knowledge on zoo-housed conspecifics and closely related species, we predicted uNeo levels to increase (1) during infections, (2) with increasing age, (3) over the gestation period and in estrous females; and (4) to vary seasonally. Our results showed uNeo levels varied over a one-year period and increased in individuals showing respiratory symptoms. Contrary to chimpanzees, uNeo levels did not vary with age or female reproductive status, possibly due to our small sample size. Our study provides a baseline for a better understanding of bonobo’s immunocompetence in the context of socio-ecological pressures and for monitoring the health of wild populations.publishe
Modulation of cell-mediated immunity during pregnancy in wild bonobos
No full textDuring pregnancy, the mammalian immune system must simultaneously protect against pathogens while being accommodating to the foreign fetal tissues. Our current understanding of this immune modulation derives predominantly from industrialized human populations and laboratory animals. However, their environments differ considerably from the pathogen-rich, resource-scarce environments in which pregnancy and the immune system co-evolved. For a better understanding of immune modulation during pregnancy in challenging environments, we measured urinary neopterin, a biomarker of cell-mediated immune responses, in 10 wild female bonobos (
Pan paniscus
) before, during and after pregnancy. Bonobos, sharing evolutionary roots and pregnancy characteristics with humans, serve as an ideal model for such investigation. Despite distinct environments, we hypothesized that cell-mediated immune modulation during pregnancy is similar between bonobos and humans. As predicted, neopterin levels were higher during than outside of pregnancy, and highest in the third trimester, with a significant decline post-partum. Our findings suggest shared mechanisms of cell-mediated immune modulation during pregnancy in bonobos and humans that are robust despite distinct environmental conditions. We propose that these patterns indicate shared immunological processes during pregnancy among hominins, and possibly other primates. This finding enhances our understanding of reproductive immunology.Department for the Ecology of Animal Societies of the Max-Planck Institute of Evolutionary AnthropologyMax Planck Institute of Animal BehaviorCentre for Research and Conservation of the Royal Zoological Society of AntwerpDeutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Ouwehand Zoo FoundationGerman Primate Center http://dx.doi.org/10.13039/501100004938Leakey Foundation http://dx.doi.org/10.13039/100005966Audacity FundInstitut Congolais pour la Conservation de la Natur
Transition to siblinghood causes a substantial and long-lasting increase in urinary cortisol levels in wild bonobos
No full textIn animals with slow ontogeny and long-term maternal investment, immatures are likely to experience the birth of a younger sibling before reaching maturity. In these species, the birth of a sibling marks a major event in an offspring's early life, as the older siblings experience a decrease in maternal support. The transition to siblinghood (TTS) is often considered to be stressful for the older offspring, but physiological evidence is lacking. To explore the TTS in wild bonobos, we investigated physiological changes in urinary cortisol (stress response), neopterin (cell-mediated immunity), and total triiodothyronine (T3, metabolic rate), as well as changes in behaviors that reflect the mother-offspring relationship. Following a sibling's birth, urinary cortisol levels of the older offspring increased fivefold, independent of their age, and remained elevated for seven months. The cortisol level increase was associated with declining neopterin levels, however T3 levels and behavioral measures did not change. Our results indicate that the TTS is accompanied by elevated cortisol levels and that this change does not coincide with nutritional weaning and attainment of physical independence. Our results suggest that bonobos and humans experience TTS in similar ways and that this developmental event may have emerged in the last common ancestor
Food begging and sharing in wild bonobos (Pan paniscus): assessing relationship quality?
No full textFood transfers are often hypothesised to have played a role in the evolution of cooperation amongst humans. However, they also occur in non-human primates, though no consensus exists regarding their function(s). We document patterns of begging for food and success rates as well as associated factors that may influence them for wild bonobos at LuiKotale, Democratic Republic of Congo. Our data, collected over 1074 observation hours, focus on 260 begging events (outside mother-offspring dyads) of which 37 % were successful. We find no support for the “reciprocity hypothesis”—that food is exchanged for grooming and/or sexual benefits; and only weak support for the “sharing under pressure” hypothesis—that food is transferred as a result of harassment and pays off in terms of nutritional benefits for the beggar. Instead, our data support the “assessing-relationships” hypothesis, according to which beggars gain information about the status of their social relationship with the possessor of a food item. This seems to hold particularly true for the frequent, albeit unsuccessful begging events by young females (newly immigrated or hierarchically non-established) towards adult females, although it can be observed in other dyadic combinations independent of sex and age
Drivers of female power in bonobos
No full textAbstract In mammals, female dominance over males is a rare phenomenon. However, recent findings indicate that even in species with sexual dimorphism biased towards males, females sometimes occupy high status. Here we test three main hypotheses explaining intersexual power relationships, namely the self-reinforcing effects of winning and losing conflicts, the strength of mate competition, and female coalition formation. We test these for bonobos ( Pan paniscus ), one of our closest living relatives, where females have high status relative to males despite male-biased size dimorphism. We compiled demographic and behavioral data of 30 years and 6 wild living communities. Our results only support predictions of the female coalition hypothesis. We found that females target males in 85% of their coalitions and that females occupy higher ranks compared to males when they form more frequent coalitions. This result indicates that female coalition formation is a behavioral tool for females to gain power over males
Cell-mediated immune ontogeny is affected by sex but not environmental context in a long-lived primate species
No full textEcoimmunology conceptualizes the role of immunity in shaping life history in a natural context. Within ecoimmunology, macroimmunology is a framework that explains the effects of habitat and spatial differences on variation in immune phenotypes across populations. Within these frameworks, immune ontogeny—the development of the immune system across an individual life span—has received little attention. Here, we investigated how immune ontogeny from birth until adulthood is affected by age, sex, and developmental environment in a long-lived primate species, the bonobo. We found a progressive, significant decline of urinary neopterin levels, a marker for the cell-mediated immune response, from birth until 5 years of age in both sexes. The overall pattern of age-related neopterin changes was sex-specific, with males having higher urinary neopterin levels than females in the first 3 years of life, and females having higher levels than males between 6 and 8 years. Environmental condition (zoohoused vs. wild) did not influence neopterin levels, nor did age-related changes in neopterin levels differ between environments. Our data suggest that the post-natal development of cell-mediated immune ontogeny is sex-specific but does not show plasticity in response to environmental conditions in this long-lived primate species. This indicates that cell-mediated immune ontogeny in the bonobo follows a stereotypic and maybe a genetically determined pattern that is not affected by environmental differences in pathogen exposure and energy availability, but that sex is an important, yet often overlooked factor shaping patterns of immune ontogeny. Investigating the causes and consequences of variation in immunity throughout life is critical for our understanding of life-history evolution and strategies, mechanisms of sexual selection, and population dynamics with respect to pathogen susceptibility. A general description of sex-specific immune ontogeny as done here is a crucial step in this direction, particularly when it is considered in the context of a species’ ecology and evolutionary history.sponsorship: Long-term data collection at LuiKotale and the zoos was funded by the Max-Planck-Society and the Royal Zoological Society of Antwerp. Additional support ensuring the collection of long-term data came from Bonobo Alive, The Federal Ministry of Education and Research (Germany), the Leakey Foundation, the Wenner-Gren Foundation, and The George Washington University. Funding for laboratory analyses was provided by the German Primate Center. Further, the study was financially supported by the Deutsche Forschungsgesellschaft (BE 5511/4-1). (Max-Planck-Society, Royal Zoological Society of Antwerp, German Primate Center, Deutsche Forschungsgesellschaft|BE 5511/4-1)status: Publishe
Wild bonobos experience unusually low bone resorption during early lactation relative to humans and other mammals
No full textIn mammals, pregnancy and lactation are marked by maternal calcium stress and bone resorption, leading to reduced bone mineral density. In humans, these periods may partly explain the higher prevalence of osteoporosis in older women compared with men, but lactation patterns in modern humans may reflect cultural influences rather than natural conditions. The extent to which these findings apply to wild-living mammals remains unknown. We measured urinary C-terminal crosslinking telopeptide of Type I collagen (CTX-I) levels, a bone resorption marker, during pregnancy in wild and zoo-housed bonobos (Pan paniscus) and during lactation in wild bonobos. Studying wild-living primates such as bonobos can provide insights into ancestral reproductive adaptations. We found an increase in CTX-I levels towards the end of pregnancy in zoo-housed and primiparous wild females. Contrary to expectations, CTX-I levels during early lactation are lower than in other reproductive phases. This pattern diverges from the assumption that lactation increases bone resorption. Our findings suggest that wild bonobos may rely on a combination of physiological and behavioral strategies to modulate bone metabolism during lactation. Bone resorption may serve as a physiological back-up when behavioral or dietary strategies cannot fully meet calcium demands. These flexible responses, shaped by fluctuating environmental conditions and prolonged maternal investment, provide insight into evolutionary pressures on skeletal health and may inform strategies to mitigate bone loss in humans
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