Center for Research and Conservation

Antwerpen, Belgium

Center for Research and Conservation

Antwerpen, Belgium
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Blooi M.,Ghent University | Pasmans F.,Ghent University | Longcore J.E.,University of Maine, United States | Spitzen-Van Der Sluijs A.,RAVON | And 2 more authors.
Journal of Clinical Microbiology | Year: 2013

Chytridiomycosis is a lethal fungal disease contributing to declines and extinctions of amphibian species worldwide. The currently used molecular screening tests for chytridiomycosis fail to detect the recently described species Batrachochytrium salamandrivorans. In this study, we present a duplex real-Time PCR that allows the simultaneous detection of B. salamandrivorans and Batrachochytrium dendrobatidis. With B. dendrobatidis- and B. salamandrivorans-specific primers and probes, detection of the two pathogens in amphibian samples is possible, with a detection limit of 0.1 genomic equivalent of zoospores of both pathogens per PCR. The developed real-Time PCR shows high degrees of specificity and sensitivity, high linear correlations (r2> 0.995), and high amplification efficiencies (>94%) for B. dendrobatidis and B. salamandrivorans. In conclusion, the described duplex real-Time PCR can be used to detect DNA of B. dendrobatidis and B. salamandrivorans with highly reproducible and reliable results.Copyright © 2013, American Society for Microbiology. All Rights Reserved.

Behringer V.,Max Planck Institute for Evolutionary Anthropology | Deschner T.,Max Planck Institute for Evolutionary Anthropology | Deimel C.,Indiana University Bloomington | Stevens J.M.G.,Center for Research and Conservation | Hohmann G.,Max Planck Institute for Evolutionary Anthropology
Hormones and Behavior | Year: 2014

Research on age-related changes in morphology, social behavior, and cognition suggests that the development of bonobos (Pan paniscus) is delayed in comparison to chimpanzees (Pan troglodytes). However, there is also evidence for earlier reproductive maturation in bonobos. Since developmental changes such as reproductive maturation are induced by a number of endocrine processes, changes in hormone levels are indicators of different developmental stages. Age-related changes in testosterone excretion are an indirect marker for the onset of puberty in human and non-human primates. In this study we investigated patterns of urinary testosterone levels in male and female bonobos and chimpanzees to determine the onset of puberty. In contrast to other studies, we found that both species experience age-related changes in urinary testosterone levels. Older individuals of both sexes had significantly higher urinary testosterone levels than younger individuals, indicating that bonobos and chimpanzees experience juvenile pause. The males of both species showed a similar pattern of age-related changes in urinary testosterone levels, with a sharp increase in levels around the age of eight years. This suggests that species-differences in aggression and male mate competition evolved independently of developmental changes in testosterone levels. Females showed a similar pattern of age-related urinary testosterone increase. However, in female bonobos the onset was about three years earlier than in female chimpanzees. The earlier rise of urinary testosterone levels in female bonobos is in line with reports of their younger age of dispersal, and suggests that female bonobos experience puberty at a younger age than female chimpanzees. © 2014 Elsevier Inc.

Tagg N.,Center for Research and Conservation | Willie J.,Center for Research and Conservation | Willie J.,Ghent University
International Journal of Primatology | Year: 2013

Monitoring populations of endangered species over time is necessary to guide and evaluate conservation efforts. This is particularly important for nonprotected areas that ensure connectivity between protected populations but are prone to uncontrolled hunting pressure. We investigated whether use of transects by local people and transect reuse for repeated surveys influence great ape nesting and bias results. We conducted simultaneous marked nest count surveys over 12 mo on established and newly opened transects in a nonprotected area subject to traditional heavy use by local people and recorded forest composition and signs of human activity. Chimpanzee and gorilla density estimates and encounter rates per kilometer were lower on established transects than on new ones. A generalized linear model indicated that hunting activity, distance to a regularly used forest trail, and transect type (old or new) predicted chimpanzee nest abundance, and distance to the trail and transect type predicted gorilla nest abundance, with no effect of habitat type (percentage suitable habitat) for either species. We, therefore, suggest that the difference in great ape nesting is a result of high levels of hunting by local people on established transects and forest trails. Our results support the use of repeated line transect surveys for monitoring great ape populations in many circumstances, although we advocate taking precautions in nonprotected areas, to avoid the bias imposed by use of established transects for hunting. © 2013 Springer Science+Business Media New York.

Callens T.,Ghent University | Galbusera P.,Center for Research and Conservation | Matthysen E.,University of Antwerp | Durand E.Y.,University of California at Berkeley | And 3 more authors.
Molecular Ecology | Year: 2011

Habitat fragmentation can restrict geneflow, reduce neighbourhood effective population size, and increase genetic drift and inbreeding in small, isolated habitat remnants. The extent to which habitat fragmentation leads to population fragmentation, however, differs among landscapes and taxa. Commonly, researchers use information on the current status of a species to predict population effects of habitat fragmentation. Such methods, however, do not convey information on species-specific responses to fragmentation. Here, we compare levels of past population differentiation, estimated from microsatellite genotypes, with contemporary dispersal rates, estimated from multi-strata capture-recapture models, to infer changes in mobility over time in seven sympatric, forest-dependent bird species of a Kenyan cloud forest archipelago. Overall, populations of sedentary species were more strongly differentiated and clustered compared to those of vagile ones, while geographical patterning suggested an important role of landscape structure in shaping genetic variation. However, five of seven species with broadly similar levels of genetic differentiation nevertheless differed substantially in their current dispersal rates. We conclude that post-fragmentation levels of vagility, without reference to past population connectivity, may not be the best predictor of how forest fragmentation affects the life history of forest-dependent species. As effective conservation strategies often hinge on accurate prediction of shifts in ecological and genetic relationships among populations, conservation practices based solely upon current population abundances or movements may, in the long term, prove to be inadequate. © 2011 Blackwell Publishing Ltd.

Etiendem D.N.,Free University of Brussels | Hens L.,Vlaamse instelling voor Technologish Onderzoek NV VITO | Pereboom Z.,Center for Research and Conservation
Ecology and Society | Year: 2011

Traditional beliefs associated with the Cross River gorilla (Gorilla gorilla diehli) in Lebialem Division, Cameroon, were studied to establish the usefulness of incorporating these local belief systems into the conservation strategy for this critically endangered species. A survey was conducted in 2007 in five villages to assess local perceptions of human-gorilla totemic kinship practices and taboos against hunting and against eating of gorillas. Villages were selected based on their proximity to Cross River gorilla (CRG) habitat, with a total of 184 interviewer-administered questionnaires completed during a 4-week period. Eighty-six percent of people agreed that gorillas were totems (personal spiritual helpers or counterparts) of people living in the village. People who believed in human-gorilla totemic kinship practice did not eat or hunt gorillas, and they wanted gorillas to be protected in order to protect the practice. Most (87%), of the interviewees declared their support for gorilla conservation. The main motivation was the belief that when gorillas are killed, the human totemic counterpart will die as a result. Because of these traditions, the hunting of gorillas is taboo in all five villages surveyed. On the other hand, gorilla parts play a direct role in traditional medicine, and gorilla bones are valued as ingredients for traditional medicine. Also, general awareness and adherence to local totemic practices was found to be declining, particularly among young people (18-25 years). Despite the imminent decline in value of belief systems that led to the establishment of the hunting taboo, this taboo is still in place and has discouraged the hunting of gorillas. Where law enforcement is weak or near inexistent, these traditional restrictions could be critical to the continuing survival of a gorilla population. Reviving and promoting beliefs and practices conducive to gorilla conservation could foster positive attitudes and behavior and have the potential to encourage local support and participation in communities. However, care must be taken when selecting practices to promote, as some (for example the use of gorillas in traditional medicine) could encourage the killing of animals. © 2011 by the author(s).

Jaeggi A.V.,University of Zürich | Stevens J.M.G.,Center for Research and Conservation | Van Schaik C.P.,University of Zürich
American Journal of Physical Anthropology | Year: 2010

Tolerant food sharing among human foragers can largely be explained by reciprocity. In contrast, food sharing among chimpanzees and bonobos may not always reflect reciprocity, which could be explained by different dominance styles: in egalitarian societies reciprocity is expressed freely, while in more despotic groups dominants may hinder reciprocity. We tested the degree of reciprocity and the influence of dominance on food sharing among chimpanzees and bonobos in two captive groups. First, we found that chimpanzees shared more frequently, more tolerantly, and more actively than bonobos. Second, among chimpanzees, food received was the best predictor of food shared, indicating reciprocal exchange, whereas among bonobos transfers were mostly unidirectional. Third, chimpanzees had a shallower and less linear dominance hierarchy, indicating that they were less despotic than bonobos. This suggests that the tolerant and reciprocal sharing found in chimpanzees, but not bonobos, was made possible by the absence of despotism. To investigate this further, we tested the relationship between despotism and reciprocity in grooming using data from an additional five groups and five different study periods on the main groups. The results showed that i) all chimpanzee groups were less despotic and groomed more reciprocally than bonobo groups, and ii) there was a general negative correlation between despotism and grooming reciprocity across species. This indicates that an egalitarian hierarchy may be more common in chimpanzees, at least in captivity, thus fostering reciprocal exchange. We conclude that a shallow dominance hierarchy was a necessary precondition for the evolution of human-like reciprocal food sharing. © 2010 Wiley-Liss, Inc.

Jaeggi A.V.,University of California at Santa Barbara | De Groot E.,Center for Research and Conservation | Stevens J.M.G.,Center for Research and Conservation | Van Schaik C.P.,University of Zürich
Evolution and Human Behavior | Year: 2013

Much of the debate about reciprocity in humans and other primates hinges on proximate mechanisms, or more precisely, the contingency of one service on another. While there is good evidence for long-term statistical contingencies of services given and received in primates, results for short-term behavioral contingencies are mixed. Indeed, as we show here controlled experiments using artificial tasks and explicit turn-taking were unlikely to find short-term effects. We therefore used more naturalistic experiments to test for short-term contingencies of grooming on food sharing and vice versa in one group of chimpanzees and two groups of bonobos. Overall, we found significant effects of grooming on food sharing and vice versa, however, in the chimpanzees these effects disappeared when controlling for long-term characteristics of the dyad including services exchanged over the whole study period. In the bonobos, short-term contingencies remained significant which was likely a consequence of considerable tension surrounding monopolizable food resulting in higher rates of grooming and other affiliative behaviors around sharing sessions. These results are consistent with the fact that previous evidence for short-term contingency often involved grooming and that long-term contingency is more commonly observed in primates. We propose that long-term contingency is proximately regulated by a 'relationship score' computed through a tally of past interactions which tend to outweigh recent single events. We therefore suggest that future research into the proximate mechanisms of reciprocity should trace the development of such a score by focusing on newly formed dyads with no history of interactions. © 2013 Elsevier Inc.

Sanz C.M.,Washington University in St. Louis | Sanz C.M.,Wildlife Conservation Society | Deblauwe I.,Institute of Tropical Medicine | Tagg N.,Center for Research and Conservation | Morgan D.B.,Wildlife Conservation Society
Journal of Human Evolution | Year: 2014

It is an ongoing interdisciplinary pursuit to identify the factors shaping the emergence and maintenance of tool technology. Field studies of several primate taxa have shown that tool using behaviors vary within and between populations. While similarity in tools over spatial and temporal scales may be the product of socially learned skills, it may also reflect adoption of convergent strategies that are tailored to specific prey features. Much has been claimed about regional variation in chimpanzee tool use, with little attention to the ecological circumstances that may have shaped such differences. This study examines chimpanzee tool use in termite gathering to evaluate the extent to which the behavior of insect prey may dictate chimpanzee technology. More specifically, we conducted a systematic comparison of chimpanzee tool use and termite prey between the Goualougo Triangle in the Republic of Congo and the La Belgique research site in southeast Cameroon. Apes at both of these sites are known to use tool sets to gather several species of termites. We collected insect specimens and measured the characteristics of their nests. Associated chimpanzee tool assemblages were documented at both sites and video recordings were conducted in the Goualougo Triangle. Although Macrotermitinae assemblages were identical, we found differences in the tools used to gather these termites. Based on measurements of the chimpanzee tools and termite nests at each site, we concluded that some characteristics of chimpanzee tools were directly related to termite nest structure. While there is a certain degree of uniformity within approaches to particular tool tasks across the species range, some aspects of regional variation in hominoid technology are likely adaptations to subtle environmental differences between populations or groups. Such microecological differences between sites do not negate the possibility of cultural transmission, as social learning may be required to transmit specific behaviors among individuals. © 2014 Elsevier Ltd.

Behringer V.,Max Planck Institute for Evolutionary Anthropology | Hohmann G.,Max Planck Institute for Evolutionary Anthropology | Stevens J.M.G.,Center for Research and Conservation | Weltring A.,Max Planck Institute for Evolutionary Anthropology | Deschner T.,Max Planck Institute for Evolutionary Anthropology
Journal of Endocrinology | Year: 2012

Adrenarche is characterized by the onset of adrenal secretions of increasing amounts of dehydroepiandrosterone-sulfate (DHEA-S). While the function of adrenarche remains a matter of speculation, evidence suggests that the morphological and physiological changes related to it are restricted to humans and closely related primates. Within the primate order, adrenarche has been described only in humans and chimpanzees, but bonobos, the sister species of chimpanzees, have not yet been studied regarding the early ontogenetic changes such as adrenarche. While bonobos and chimpanzees share many morphological and behavioral characteristics, they differ in a number of behavioral traits, and there is a growing interest in terms of the physiological differences that can be linked to species-specific patterns of social behavior. In this study, we measured urinary DHEA-S levels to determine whether bonobos experience physiological changes that are indicative of adrenarche. We measured DHEA-S in urine using ELISA and analyzed its levels in the samples from 53 bonobos aged 1-18 years. Our results show that bonobos experience an increase in DHEA-S levels after 5 years of age, which is comparable with the patterns observed in humans and chimpanzees. This indicates that bonobos do undergo adrenarche and that the timing of onset is similar to that of the two Pan species. The extraction procedures described in this report demonstrate the use of urine for monitoring ontogenetic changes in DHEA-S excretion. If applicable to other species, the technique would facilitate more research on the evolutionary origin of adrenarche and other developmental processes. © 2012 Society for Endocrinology.

Stevens J.M.G.,Center for Research and Conservation | De Groot E.,Center for Research and Conservation | Staes N.,Center for Research and Conservation | Staes N.,University of Antwerp
Behaviour | Year: 2015

We use Principal Component Analyses (PCA) to describe components of social relationship quality in bonobos. We find a three component structure, with the first two components, labelled Value and Compatibility, closely matching the theoretical constructs as well as components reported for chimpanzees and other primates. The third component differed but was abandoned based on Parallel Analysis. Among bonobos, female-female dyads have higher Value and Compatibility. Relationships between males are characterised by low Value and Compatibility. Dyads that had been housed together for a longer time and maternally related ones also have more valuable relationships, while individuals close in rank have low compatibility. The results confirm the strong bonds among female bonobos, but for the first time can describe how they differ qualitatively from close bonds reported for captive chimpanzee females.We suggest future studies should also include Parallel Analysis to more accurately describe the number of components in relationship quality. © 2015 Koninklijke Brill NV, Leiden.

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