7 research outputs found
Early maternal loss leads to short-but not long-term effects on diurnal cortisol slopes in wild chimpanzees
The biological embedding model (BEM) suggests that fitness costs of maternal loss arise when early-life experience embeds long-term alterations to hypothalamic-pituitary-adrenal (HPA) axis activity. Alternatively, the adaptive calibration model (ACM) regards physiological changes during ontogeny as short-term adaptations. Both models have been tested in humans but rarely in wild, long-lived animals. We assessed whether, as in humans, maternal loss had short-and long-term impacts on orphan wild chimpanzee urinary cortisol levels and diurnal urinary cortisol slopes, both indicative of HPA axis functioning. Immature chimpanzees recently orphaned and/or orphaned early in life had diurnal cortisol slopes reflecting heightened activation of the HPA axis. However, these effects appeared short-term, with no consistent differences between orphan and non-orphan cortisol profiles in mature males, suggesting stronger support for the ACM than the BEM in wild chimpan-zees. Compensatory mechanisms, such as adoption, may buffer against certain physiological effects of maternal loss in this species
Quantifying within-group variation in socialityâcovariation among metrics and patterns across primate groups and species
It has long been recognized that the patterning of social interactions within a group can give rise to a social structure that holds very different places for different individuals. Such within-group variation in sociality correlates with fitness proxies in fish, birds, and mammals. Broader integration of this research has been hampered by the lack of agreement on how to integrate information from a plethora of dyadic interactions into individual-level metrics. As a step towards standardization, we collected comparative data on affinitive and affiliative interactions from multiple groups each of five species of primates to assess whether the same aspects of sociality are measured by different metrics and indices. We calculated 16 different sociality metrics used in previous research and thought to represent three different sociality concepts. We assessed covariation of metrics within groups and then summarized covariation patterns across all 15 study groups, which varied in size from 5 to 41 adults. With some methodological and conceptual caveats, we found that the number of weak ties individuals formed within their groups represented a dimension of sociality that was largely independent from the overall number of ties as well as from the number and strength of the strong ties they formed. Metrics quantifying indirect connectedness exhibited strong covariation with strong tie metrics and thus failed to capture a third aspect of sociality. Future research linking affiliation and affinity to fitness or other individual level outcomes should quantify inter-individual variation in three aspects: the overall number of ties, the number of weak ties, and the number or strength of strong ties individuals form, after taking into account effects of social network density.
Significance statement:
In recent years, long-term studies of individually known animals have revealed strong correlations between individual social bonds and social integration, on the one hand, and reproductive success and survival on the other hand, suggesting strong natural selection on affiliative and affinitive behavior within groups. It proved difficult to generalize from these studies because they all measured sociality in slightly different ways. Analyzing covariation between 16 previously used metrics identified only three rather independent dimensions of variation. Thus, different studies have tapped into the same biological phenomenon. How individuals are weakly connected within their group needs further attention.Peer Reviewe
Shared community effects and the non-genetic maternal environment shape cortisol levels in wild chimpanzees
Mechanisms of inheritance remain poorly defined for many fitness-mediating traits, especially in long-lived animals with protracted development. Using 6,123 urinary samples from 170 wild chimpanzees, we examined the contributions of genetics, non-genetic maternal effects, and shared community effects on variation in cortisol levels, an established predictor of survival in long-lived primates. Despite evidence for consistent individual variation in cortisol levels across years, between-group effects were more influential and made an overwhelming contribution to variation in this trait. Focusing on within-group variation, non-genetic maternal effects accounted for 8% of the individual differences in average cortisol levels, significantly more than that attributable to genetic factors, which was indistinguishable from zero. These maternal effects are consistent with a primary role of a shared environment in shaping physiology. For chimpanzees, and perhaps other species with long life histories, community and maternal effects appear more relevant than genetic inheritance in shaping key physiological traits.Additional co-authors: Klaus Zuberbuehler, Linda Vigilant, Tobias Deschner, Roman M. Wittig & Catherine Crockfor
Suivi du comportement sexuel chez 3 espĂšces de primates non-humains du genre Nomascus
Cette Ă©tude sâinscrit dans un suivi Ă long terme des effets dâun contraceptif progestatif sur le comportement reproducteur. Peu de donnĂ©es Ă©tant disponibles, un suivi de la reproduction, au prĂ©alable de lâimplantation, est donc essentiel afin de dĂ©finir des indicateurs comportementaux. Un Ă©chantillonnage par individu focal et un suivi hormonal sont effectuĂ©s de maniĂšre concomitante sur 3 groupes de primates non-humains du genre Nomascus (N. siki, N. leucogenys et N. gabriellae). Les groupes sont constituĂ©s respectivement de (1) 1 mĂąle et sa progĂ©niture : une femelle adulte, un mĂąle subadulte et un jeuneâ; (2) un mĂąle adulte, une femelle adulte et sa progĂ©niture femelle adulteâ; (3) un couple dâadultes, une femelle subadulte et un jeune. Le suivi comportemental, se dĂ©roulant sur 3 h, 15 minutes par individu, 5 jours par semaine de fĂ©vrier Ă avril 2015, vise Ă repĂ©rer des diffĂ©rences dans le comportement de la femelle au cours du temps et si les variations observĂ©es sont en relation avec les variations hormonales. Au cours de ces 123 heures 45 minutes d'observations, des comportements sexuels ont pu ĂȘtre observĂ©s chez 2 des 3 groupes de Nomascus durant les 9 semaines dâobservations. Au sein du groupe leucogenys, la plus jeune femelle Ă©met 64 invitations et 1 accouplement tandis que la seconde Ă©met 10 invitations et 1 prĂ©sentation. Aucune diffĂ©rence significative dans le comportement nâest observĂ©e pour la femelle du groupe leucogenys. De plus il semble que lâĂ©mission des comportements reproducteurs n'est pas dĂ©pendante du niveau hormonal (corrĂ©lation de Spearman). Chez le groupe gabriellae, les deux femelles ont exprimĂ© des comportements sexuels, 30 invitations et 10 accouplements et 3 prĂ©sentations ont Ă©tĂ© Ă©mis par la femelle suivie hormonalement. La femelle subadulte a effectuĂ© 3 prĂ©sentations. Il nây a pas de diffĂ©rence significative dans le nombre ou la durĂ©e des interactions Ă©mises par la femelle N. gabriellae ni en fonction du temps ni en fonction du rĂ©cepteur, cependant, la femelle interagit significativement plus (frĂ©quence et durĂ©e) avec le mĂąle durant 3 des 9 semaines que le reste du temps (test de wilcoxon, p = 0,02268 et p = 0,001745). Câest lors de ces 3 semaines que les comportements reproducteurs ont Ă©tĂ© observĂ©s. Lâexpression des comportements reproducteurs nâest pas indĂ©pendante des niveaux hormonaux (corrĂ©lation de Spearman, p = 4,065.10-4). Au regard des rĂ©sultats, il existe une indĂ©pendance relative entre les comportements reproducteurs et le contrĂŽle hormonal. Il semble donc important de dissocier les comportements sexuels reproducteurs et sociaux. Un suivi comportemental de la reproduction est possible par lâobservation de comportements sexuels discriminants. Cependant ces rĂ©sultats sont Ă relativiser, car les observations nâont portĂ© que sur 5 % de la durĂ©e totale dâun cycle. De plus les comportements sexuels sont de courte durĂ©e et peuvent facilement Ă©chapper Ă lâobservateur. Enfin un faible nombre de femelles et de cycles suivis (n = 2) ne permet pas de sâaffranchir des variations individuelles. Pour cela il est nĂ©cessaire dâaugmenter lâĂ©chantillonnage de femelles et de cycles.Je souhaite remercier lâensemble des soigneurs du Parc zoologique et botanique de Mulhouse en particulier les soigneurs des secteurs lĂ©muriens, le Dr J. Y. Georges pour son aide dans lâanalyse des donnĂ©es et son savoir-faire
Evaluation dâune mĂ©thode de suivi des cycles sexuels par dosage des stĂ©roĂŻdes fĂ©caux chez deux espĂšces de primates non-humains
Les contraceptifs hormonaux sont des outils trĂšs utilisĂ©s pour la gestion des populations de primates en parc zoologique, mais leur maĂźtrise est actuellement une problĂ©matique majeure. En effet, leur impact sur les cycles, la santĂ© et le comportement est mal connu, et leur efficacitĂ© semble inconstante. Cette Ă©tude a pour objet dâĂ©tablir un protocole biologique permettant le suivi de la reproduction par dosages des hormones sexuelles dans les selles. Cette mĂ©thode est utilisĂ©e depuis longtemps chez de nombreuses espĂšces sauvages, en particulier grands herbivores et carnivores, mais plus rarement chez les primates. Elle permet de mettre en Ă©vidence une activitĂ© sexuelle voire une cyclicitĂ© chez les femelles, de confirmer des gestations, et pourrait aussi permettre dâĂ©valuer les effets et lâefficacitĂ© des contraceptifs. Notre Ă©tude est rĂ©alisĂ©e en parc zoologique chez les gibbons Ă favoris (Nomascus gabriellae et Nomascus leucogenys) et les capucins Ă poitrine jaune (Sapajus xanthosternos). Deux hormones ont Ă©tĂ© mesurĂ©es : lâĆstradiol et la progestĂ©rone. Les fĂšces des femelles ont Ă©tĂ© rĂ©coltĂ©es individuellement Ă 2 ou 3 jours dâintervalle pendant 10 semaines. Les prĂ©lĂšvements, congelĂ©s rapidement aprĂšs rĂ©colte, ont ensuite Ă©tĂ© transfĂ©rĂ©s au laboratoire LDHVet, Ecole VĂ©tĂ©rinaire Oniris (Nantes) pour y ĂȘtre traitĂ©s. Les dosages hormonaux dans les selles nĂ©cessitent une Ă©tape de prĂ©paration des Ă©chantillons : dessiccation (24 h), suivie dâun broyage puis dâune extraction par solvant organique (MeOH). AprĂšs Ă©vaporation, cet extrait est repris avec une solution de BSA (tampon) avant dâĂȘtre dosĂ©. La progestĂ©rone a Ă©tĂ© dosĂ©e par radio-immunologie (RIA), et lâĆstradiol 17-ÎČ par immuno-enzymologie (EIA). Les premiers rĂ©sultats montrent des variations hormonales qui rĂ©vĂšlent des activitĂ©s folliculaires (production dâĆstradiol 17-ÎČ) et lutĂ©iniques (production de progestĂ©rone) permettant chez certaines femelles dâidentifier des cycles clairs, ce qui montre que la mĂ©thode est envisageable pour le suivi des primates non-humains en parc zoologique. LâĂ©valuation de cette mĂ©thode de suivi des cycles sexuels par dosage des stĂ©roĂŻdes fĂ©caux constitue une Ă©tape prĂ©liminaire Ă une Ă©tude plus large. Outre son application directe pour le suivi des femelles, elle pourra servir de base dans lâĂ©tude de lâimpact et de lâefficacitĂ© des mĂ©thodes contraceptives. Sont notamment ciblĂ©s les implants progestatifs Ă base dâĂ©tonogestrel, largement utilisĂ©s, dont lâefficacitĂ© fait rĂ©guliĂšrement dĂ©faut chez certaines espĂšces (CĂ©bidĂ©s, CallithricidĂ©s) et qui pourraient ĂȘtre toxiques (effets mĂ©taboliques dont diabĂ©togĂšnes) surtout en cas de traitements rĂ©pĂ©tĂ©s
Shared community effects and the non-genetic maternal environment shape cortisol levels in wild chimpanzees
This study was funded by the Max Planck Society and the European Research Council (ERC) under the European Unionâs Horizon 2020 research and innovation program awarded to C.C. (grant agreement no. 679787). L.S. was supported by the Minerva Foundation, C.Y.A. and A.P. received funding from the LSB Leakey Foundation, C.Y.A. also received funding from Subvention EgalitĂ© (University of NeuchĂątel, Switzerland) and Fonds des Donations (University of NeuchĂątel, Switzerland). C.G. was supported by the Wenner-Gren Foundation. VM was supported by a grant of Deutsche Forschungsgemeinschaft (DFG) granted to R.M.W. (WI 2637/3-1). Core funding for the TaĂŻ Chimpanzee Project was provided by the Max Planck Society since 1997 and for Budongo Conservation Field Station by the Royal Zoological Society of Scotland since 2008.Mechanisms of inheritance remain poorly defined for many fitness-mediating traits, especially in long-lived animals with protracted development. Using 6,123 urinary samples from 170 wild chimpanzees, we examined the contributions of genetics, non-genetic maternal effects, and shared community effects on variation in cortisol levels, an established predictor of survival in long-lived primates. Despite evidence for consistent individual variation in cortisol levels across years, between-group effects were more influential and made an overwhelming contribution to variation in this trait. Focusing on within-group variation, non-genetic maternal effects accounted for 8% of the individual differences in average cortisol levels, significantly more than that attributable to genetic factors, which was indistinguishable from zero. These maternal effects are consistent with a primary role of a shared environment in shaping physiology. For chimpanzees, and perhaps other species with long life histories, community and maternal effects appear more relevant than genetic inheritance in shaping key physiological traits.Publisher PDFPeer reviewe