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Alban Lemasson - One of the best experts on this subject based on the ideXlab platform.

  • red capped mangabeys Cercocebus torquatus adapt their interspecific gestural communication to the recipient s behaviour
    Scientific Reports, 2020
    Co-Authors: Juliette Aychet, Pablo Pezzino, Arnaud Rossard, Philippe Bec, Catherine Bloisheulin, Alban Lemasson
    Abstract:

    Sensitivity to recipient’s attention and responsiveness are critical markers of intentional communication. Although previous research showed that ape gestures can be intentional, few studies have yet addressed this question concerning monkeys. Here, we characterise the effect of a recipient’s presence, attentional state and responsiveness on the interspecific gestural communication of captive red-capped mangabeys (Cercocebus torquatus). Previous reports showed that they produced learnt begging gestures towards a human recipient preferentially when the latter was facing them. We used here a novel setup that allows subjects to move around an experimenter and to use different modalities (visual and acoustic) to communicate. We found that when the recipient was not facing them, mangabeys moved to a position in the visual field of their recipient rather than using attention-getters. Interestingly, unlike apes, they did not elaborate their communication visually or acoustically when the experimenter did not respond favourably to their begging. However, our results may suggest that begging gestures were goal-directed, since mangabeys inhibited them when the experimenter was not available to answer immediately (i.e. give a reward). Overall, red-capped mangabeys’ interspecific visual communication presented intentionality features, but their use of begging gestures was less flexible than that of great apes in similar situations.

  • Acoustic variability and individual distinctiveness in the vocal repertoire of red-capped mangabeys (Cercocebus torquatus).
    Journal of Comparative Psychology, 2012
    Co-Authors: Hélène Bouchet, Catherine Blois-heulin, Anne-sophie Pellier, Klaus Zuberbühler, Alban Lemasson
    Abstract:

    Acoustic variability and individual distinctiveness of vocal signals are expected to vary with both their communicative function and the need for individual recognition during social interactions. So far, few attempts have been made to comparatively study these features across the different call types within a species' vocal repertoire. We collected recordings of the six most common call types from 14 red-capped mangabeys (Cercocebus torquatus) to assess intra- and interindividual acoustic variability, using a range of temporal and frequency parameters. Acoustic variability was highest in contact and threat calls, intermediate in food calls, and lowest in loud and alarm calls. Individual distinctiveness was high in contact, threat, loud and alarm calls, and low in food calls. In sum, calls mediating intragroup social interactions were structurally most variable and individually most distinctive, highlighting the key role that social factors must have played in the evolution of the vocal repertoire in this species. We discuss these findings in light of existing hypotheses of acoustic variability in primate vocal behavior.

Christopher C Gilbert - One of the best experts on this subject based on the ideXlab platform.

  • phylogenetic relationships within the Cercocebus mandrillus clade as indicated by craniodental morphology implications for evolutionary biogeography
    American Journal of Physical Anthropology, 2015
    Co-Authors: Lieven Devreese, Christopher C Gilbert
    Abstract:

    Objective The African papionin primates commonly known as mangabeys form a diphyletic group with white-eyelid mangabeys (Cercocebus) being most closely related to drills and mandrills (Mandrillus). However, the phylogenetic relationships among members of the Cercocebus–Mandrillus clade have not been investigated in detail, particularly from a morphological perspective. Early studies of white-eyelid mangabeys considered C. agilis to best represent the ancestral lineage and C. torquatus as the most derived species, the result of multiple biogeographic dispersal events. More recently, a sister-clade relationship between Mandrillus and either C. chrysogaster or C. torquatus has been proposed. Materials and Methods Here we present the results of phylogenetic analyses based on 206 craniodental characters (103 representing males and females separately) of four species of Cercocebus and both species of Mandrillus. Results When all species of the Cercocebus–Mandrillus clade are analyzed without molecular constraints, results suggest that C. torquatus may indeed be more closely related to mandrills and drills than to other Cercocebus taxa. However, this topology lacks strong statistical support and may be attributable to incomplete lineage sorting and/or reticulation. When we employ a molecular backbone to constrain Cercocebus and Mandrillus monophyly, C. torquatus appears most basal, while C. agilis and C. chrysogaster form a derived clade. Discussion The molecular backbone view is also congruent with recent genetic analyses and assessments based on the fossil record, but awaits confirmation with additional data. This phylogeny suggests that Cercocebus and Cercocebus + Mandrillus arose in western equatorial Africa with subsequent dispersals westward, eastward, and possibly southward over the last > 3 million years. Am J Phys Anthropol 158:227–241, 2015. © 2015 Wiley Periodicals, Inc.

  • craniomandibular morphology supporting the diphyletic origin of mangabeys and a new genus of the Cercocebus mandrillus clade proCercocebus
    Journal of Human Evolution, 2007
    Co-Authors: Christopher C Gilbert
    Abstract:

    Abstract Previous studies have noted skeletal and dental differences supporting the diphyletic origin of the mangabeys. Documented postcranial and dental characters are congruent with molecular data and thus support a close relationship between Cercocebus and Mandrillus (mandrills and drills) on the one hand and Lophocebus, Papio (baboons), and Theropithecus (geladas) on the other. Most of these characters, however, are postcranial and difficult to assess in the papionin fossil record because associated material is rare. In order to assess the African papionin fossil record and determine the evolutionary history of this group, cranial characters are critical. Here, a set of craniomandibular morphologies are documented that support the diphyletic origin of the mangabeys and more broadly support the molecular African papionin clades (i.e., Cercocebus/Mandrillus vs. Lophocebus/Papio/Theropithecus). These characters are then used to identify a series of fossil crania from Taung as representative of a new member of the Cercocebus/Mandrillus clade, ProCercocebus antiquus. ProCercocebus antiquus is closest in morphology to the extant taxon Cercocebus torquatus, and a probable ancestor-descendant relationship between ProCercocebus and Cercocebus is suggested. Paleoecological reconstructions also suggest that a predator-prey relationship between African crowned eagles and the ProCercocebus-Cercocebus lineage has existed for approximately the last two million years. Implications for Cercocebus biogeography and evolution are discussed.

Christos Astaras - One of the best experts on this subject based on the ideXlab platform.

  • associations between the drill mandrillus leucophaeus and sympatric monkeys in korup national park cameroon
    American Journal of Primatology, 2011
    Co-Authors: Lutz Mattner, Christoph Rehse, Christos Astaras, Stefan Krause, Matthias Waltert
    Abstract:

    Studies of polyspecific associations among African forest primates have primarily focused on arboreal Cercopithecus and Procolobus/Colobus species. We examined the association frequency of the terrestrial drill (Mandrillus leucophaeus) with six sympatric monkey species in Korup National Park, Cameroon, testing reports that Mandrillus associations are infrequent and transient. We conducted 3,284 km of trail walks for 12 months (February–June 2006; July 2007 to January 2008), recording species composition in 612 primate clusters. Using a Markov chain Monte Carlo test, we compared the observed frequency of dyadic associations against null models of “no association.” A novel conservative statistical approach which addresses possible dependence of observations close in time was also used, further strengthening confidence in our findings. Drills associated with all monkeys throughout the study period, and were with at least one other species (range 1–5) in half of the encounters. The association frequency of drills with red-capped mangabeys (Cercocebus torquatus) was greater than expected by chance, which is interesting given the morphological adaptation of the Mandrillus-Cercocebus clade for the exploitation of the same dietary niche, hard seeds. The difference we observed in the use of forest strata by drills and mangabeys may reflect a strategy to reduce food competition while in association. The nature and duration of observed drill associations varied. Although some associations seemed to be chance encounters, others lasted for hours with the involved species foraging together. Am. J. Primatol. 73:127–134, 2011. © 2010 Wiley-Liss, Inc.

  • research article associations between the drill mandrillus leucophaeus and sympatric monkeys in korup national park cameroon
    2011
    Co-Authors: Christos Astaras, Lutz Mattner, Christoph Rehse, Stefan Krause, Matthias Waltert
    Abstract:

    Studies of polyspecific associations among African forest primates have primarily focused on arboreal Cercopithecus and Procolobus/Colobus species. We examined the association frequency of the terrestrial drill (Mandrillus leucophaeus) with six sympatric monkey species in Korup National Park, Cameroon, testing reports that Mandrillus associations are infrequent and transient. We conducted 3,284km of trail walks for 12 months (February‐June 2006; July 2007 to January 2008), recording species composition in 612 primate clusters. Using a Markov chain Monte Carlo test, we compared the observed frequency of dyadic associations against null models of ‘‘no association.’’ A novel conservative statistical approach which addresses possible dependence of observations close in time was also used, further strengthening confidence in our findings. Drills associated with all monkeys throughout the study period, and were with at least one other species (range 1‐5) in half of the encounters. The association frequency of drills with red-capped mangabeys (Cercocebus torquatus) was greater than expected by chance, which is interesting given the morphological adaptation of the Mandrillus-Cercocebus clade for the exploitation of the same dietary niche, hard seeds. The difference we observed in the use of forest strata by drills and mangabeys may reflect a strategy to reduce food competition while in association. The nature and duration of observed drill associations varied. Although some associations seemed to be chance encounters, others lasted for hours with the involved species foraging together. Am. J. Primatol. 73:127‐134, 2011. r 2010 Wiley-Liss, Inc.

Friederike Range - One of the best experts on this subject based on the ideXlab platform.

  • 7
    2015
    Co-Authors: Friederike Range, Julia Fischer
    Abstract:

    Recordings of sooty mangabeys (Cercocebus torquatus atys) in their natural environment were used to compile the vocal repertoire of this species. All calls are described according to their acoustic features and the behavioural context in which they occurred. Descriptions are supplemented by quantitative measurements of call occurrence of all age-sex classes. This study was designed to increase our understanding of the influence of phylogeny and habitat constraints on the acoustic features of vocalizations by filling the gap of our knowledge about vocalizations of terrestrial old world primates that live in dense rainforests

  • female sooty mangabeys Cercocebus torquatus atys respond differently to males depending on the male s residence status preliminary data
    American Journal of Primatology, 2005
    Co-Authors: Friederike Range
    Abstract:

    I tested the hypothesis that free-ranging female mangabeys (Cercocebus torquatus atys) differentiate between males depending on their residence status. Adult males in this species employ two group-membership strategies: they are either full-time residents or part-time residents (i.e., present for several weeks at a time, then gone for several weeks, then present again, etc.). In a playback experiment I tested whether adult females with young infants responded differently to calls of adult males that were group members during the previous mating season as compared to males that belonged to neighboring groups during the mating season or were complete strangers. Males whose calls were played were present residents, part-time residents (absent for at least 3 months), neighbors, or complete strangers. Because infanticide is a potential risk in mangabeys, I predicted that females would respond differently to males that had resided in the group when their infant was conceived than they would to those that had not been present. The females showed a clear difference in their reaction to the playbacks of vocalizations from resident and part-time resident males as opposed to nonresidents.

  • vocal repertoire of sooty mangabeys Cercocebus torquatus atys in the tai national park
    Ethology, 2004
    Co-Authors: Friederike Range, Julia Fischer
    Abstract:

    Three factors, environment, quality and type of interaction, and phylogeny have been hypothesized to influence the structure of signal repertoires in primates. Much is known about vocal repertoires of terrestrial, savannah-dwelling species and arboreal, rainforest-dwelling species, but very little is known about terrestrial rainforest species. To fill this knowledge gap and to further elucidate how the three factors influence vocal repertoires of primates, we designed a study on sooty mangabeys (Cercocebus torquatus atys), a terrestrial Old World primate that lives in dense rainforests. Recordings of sooty mangabeys in their natural environment were used to compile the vocal repertoire of this species. All calls are described according to the basic acoustical structure and the behavioral context in which they occurred. Descriptions are supplemented by quantitative measurements of call occurrence in all age-sex classes. For the most frequently produced vocalizations, a preliminary acoustical analysis was conducted to test for individual and contextual differences. Finally, we compare vocalizations of sooty mangabeys with vocalizations of several other primate species and discuss how the factors mentioned above might influence the vocal repertoire of sooty mangabeys.

Beatrice H. Hahn - One of the best experts on this subject based on the ideXlab platform.

  • Link between Primate Lentiviral Coreceptor Usage and Nef Function
    Cell reports, 2013
    Co-Authors: Jan Schmökel, Beatrice H. Hahn, Guido Silvestri, Asma Shabir, Matthias Geyer, Donald L. Sodora, Frank Kirchhoff
    Abstract:

    Summary Simian immunodeficiency virus (SIVsmm) infection of sooty mangabeys ( Cercocebus atys ) is characterized by stable CD4 + T cell counts despite high plasma levels of CCR5-tropic viruses. However, in rare instances, SIVsmm acquires CXCR4 coreceptor tropism and causes severe CD4 + T cell depletion, albeit without clinical signs of immunodeficiency. Here, we show that CXCR4-tropic SIVsmm strains lost their ability to downmodulate TCR-CD3 by evolving unusual Nef mutations that initially reduced (I132V) and subsequently disrupted (I123L and L146F) interaction with the CD3 ζ chain. This coevolution of Env and Nef function suggests that CD3 downmodulation is advantageous for viral replication in activated CCR5 + memory T cells, but not in resting naive CXCR4 + T cells that have not yet undergone TCR-CD3-mediated stimulation. This may explain why HIV-1, which generally lacks the CD3 downmodulation function, commonly switches to CXCR4 usage, whereas this is extremely rare for SIV strains that have retained this Nef activity.

  • Simian Immunodeficiency Virus Infection of Chimpanzees
    Journal of virology, 2005
    Co-Authors: Paul M. Sharp, George M. Shaw, Beatrice H. Hahn
    Abstract:

    Simian immunodeficiency viruses (SIVs) are primate lentiviruses that infect no fewer than 36 different nonhuman primate species in sub-Saharan Africa ([4][1], [9][2], [62][3]). Two of these viruses, SIVcpz from chimpanzees ( Pan troglodytes ) and SIVsmm from sooty mangabeys ( Cercocebus atys ), have