News Article | April 18, 2017
Captive meerkats often live in groups so small that they would be very vulnerable in the wild and—although they are not at risk from predators—being in a larger group might make them feel safer. Living in small enclosures and being constantly exposed to high numbers of human visitors also increase stress, according to scientists from the University of Exeter. The researchers measured stress by looking at hormone levels in the meerkats' droppings. "Animals in zoos may be stressed despite not showing obvious behavioural problems," said senior author Dr Emma Vitikainen, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall. "Meerkat group sizes in captivity tend to be closer to those seen in small unstable groups in the wild, which may represent a stressful condition and predispose meerkats to chronic stress, even in the absence of natural predators."Our results are consistent with the theory that there is an optimum group size which minimises physiological stress in meerkats, and that zoo meerkats at most risk are those kept in small groups and small enclosures, and those which are exposed to consistently high numbers of visitors." Wild meerkats usually live in groups of 20-30. Eight UK zoos and wildlife parks took part in the study. Lead author Dr Katy Scott, who collaborated closely with the zoos to collect samples, said: "We are grateful for their support and cooperation and we hope these results will be useful to zoos and wildlife parks in caring for their meerkats." In contrast with data from wild meerkats, the study found that neither sex, age nor dominance status affected stress levels—possibly because access to food is more equal in captivity. The research was carried out with help from the German Primate Centre, Leibniz Institute for Primate Research in Göttingen, Germany. Explore further: 'Mean girl' meerkats can make twice as much testosterone as males More information: Group size and visitor numbers predict faecal glucocorticoid concentrations in zoo meerkats, Royal Society Open Science, rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.161017
News Article | April 18, 2017
Small groups of meerkats -- such as those commonly seen in zoos and safari parks -- are at greater risk of chronic stress, new research suggests. Captive meerkats often live in groups so small that they would be very vulnerable in the wild and -- although they are not at risk from predators -- being in a larger group might make them feel safer. Living in small enclosures and being constantly exposed to high numbers of human visitors also increase stress, according to scientists from the University of Exeter. The researchers measured stress by looking at hormone levels in the meerkats' droppings. "Animals in zoos may be stressed despite not showing obvious behavioural problems," said senior author Dr Emma Vitikainen, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall. "Meerkat group sizes in captivity tend to be closer to those seen in small unstable groups in the wild, which may represent a stressful condition and predispose meerkats to chronic stress, even in the absence of natural predators. "Our results are consistent with the theory that there is an optimum group size which minimises physiological stress in meerkats, and that zoo meerkats at most risk are those kept in small groups and small enclosures, and those which are exposed to consistently high numbers of visitors." Wild meerkats usually live in groups of 20-30. Eight UK zoos and wildlife parks took part in the study. Lead author Dr Katy Scott, who collaborated closely with the zoos to collect samples, said: "We are grateful for their support and cooperation and we hope these results will be useful to zoos and wildlife parks in caring for their meerkats." In contrast with data from wild meerkats, the study found that neither sex, age nor dominance status affected stress levels -- possibly because access to food is more equal in captivity. The research was carried out with help from the German Primate Centre, Leibniz Institute for Primate Research in Göttingen, Germany. The paper, entitled: "Group size and visitor numbers predict faecal glucocorticoid concentrations in zoo meerkats", is published in the journal Royal Society Open Science.
Fuchs E.,Leibniz Institute for Primate Research |
Fuchs E.,University of Gottingen |
Flugge G.,Leibniz Institute for Primate Research
Neural Plasticity | Year: 2014
Within the last four decades, our view of the mature vertebrate brain has changed significantly. Today it is generally accepted that the adult brain is far from being fixed. A number of factors such as stress, adrenal and gonadal hormones, neurotransmitters, growth factors, certain drugs, environmental stimulation, learning, and aging change neuronal structures and functions. The processes that these factors may induce are morphological alterations in brain areas, changes in neuron morphology, network alterations including changes in neuronal connectivity, the generation of new neurons (neurogenesis), and neurobiochemical changes. Here we review several aspects of neuroplasticity and discuss the functional implications of the neuroplastic capacities of the adult and differentiated brain with reference to the history of their discovery. © 2014 Eberhard Fuchs and Gabriele Flügge.
Wahab F.,Leibniz Institute for Primate Research |
Shahab M.,Quaid-i-Azam University |
Behr R.,Leibniz Institute for Primate Research
Journal of Endocrinology | Year: 2015
Recently, kisspeptin (KP) and gonadotropin inhibitory hormone (GnIH), two counteracting neuropeptides, have been acknowledged as significant regulators of reproductive function. KP stimulates reproduction while GnIH inhibits it. These two neuropeptides seem to be pivotal for the modulation of reproductive activity in response to internal and external cues. It is well-documented that the current metabolic status of the body is closely linked to its reproductive output. However, how reproductive function is regulated by the body's energy status is less clear. Recent studies have suggested an active participation of hypothalamic KP and GnIH in the modulation of reproductive function according to available metabolic cues. Expression of KISS1, the KP encoding gene, is decreased while expression of RFRP (NPVF), the gene encoding GnIH, is increased in metabolic deficiency conditions. The lower levels of KP, as suggested by a decrease in KISS1 gene mRNA expression, during metabolic deficiency can be corrected by administration of exogenous KP, which leads to an increase in reproductive hormone levels. Likewise, administration of RF9, a GnIH receptor antagonist, can reverse the inhibitory effect of fasting on testosterone in monkeys. Together, it is likely that the integrated function of both these hypothalamic neuropeptides works as a reproductive output regulator in response to a change in metabolic status. In this review, we have summarized literature from nonprimate and primate studies that demonstrate the involvement of KP and GnIH in the metabolic regulation of reproduction. © 2015 The authors.
Eildermann K.,Leibniz Institute for Primate Research |
Gromoll J.,University of Mnster |
Behr R.,Leibniz Institute for Primate Research
Human Reproduction | Year: 2012
Background: Several studies have reported the generation of spermatogonia-derived pluripotent stem cells from human testes. The initial aim of the present study was the derivation of equivalent stem cells from an established and experimentally accessible non-human primate model, the common marmoset monkey (Callithrix jacchus). However, an essential prerequisite in the absence of transgenic reporters in primates and man is the availability of validated endogenous markers for the identification of specific cell types in vitro. Methods AND Results We cultured marmoset testicular cells in a similar way to that described for human testis-derived pluripotent cells and set out to characterize these cultures under different conditions and in differentiation assays applying established marker panels. Importantly, the cells emerged as testicular multipotent stromal cells (TMSCs) instead of (pluripotent) germ cell-derived cells. TMSCs expressed many markers such as GFR-α, GPR125, THY-1 (CD90), ITGA6, SSEA4 and TRA-1-81, which were considered as spermatogonia specific and were previously used for the enrichment or characterization of spermatogonia. Proliferation of TMSCs was highly dependent on basic fibroblast growth factor, a growth factor routinely present in germ cell culture media. As reliable markers for the distinction between spermatogonia and TMSCs, we established VASA, in combination with the spermatogonia-expressed factors, MAGEA4, PLZF and SALL4. Conclusions Marmoset monkey TMSCs and spermatogonia exhibit an overlap of markers, which may cause erroneous interpretations of experiments with testis-derived stem cells in vitro. We provide a marker panel for the unequivocal identification of spermatogonia providing a better basis for future studies on primate, including human, testis-derived stem cells. © 2012 The Author.
Klippert A.,Leibniz Institute for Primate Research
Immunology and Cell Biology | Year: 2016
Granzyme B-expressing (GrB+) B cells are thought to contribute to immune dysfunctions in HIV patients, but so far their exact role is unknown. This report demonstrates for the first time the existence of GrB+ B cells in SIV-infected rhesus macaques, which represent the most commonly used nonhuman primate model for HIV research. Similar to HIV patients, we found significantly higher frequencies of these cells in the blood of chronically SIV-infected rhesus monkeys compared with uninfected healthy ones. These frequencies correlated with plasma viral load and inversely with absolute CD4 T-cell counts. When investigating GrB+ B cells in different compartments, levels were highest in blood, spleen and bone marrow, but considerably lower in lymph nodes and tonsils. Analysis of expression of various surface markers on this particular B-cell subset in SIV-infected macaques revealed differences between the phenotype in macaques and in humans. GrB+ B cells in SIV-infected rhesus macaques exhibit an elevated expression of CD5, CD10, CD25 and CD27, while expression of CD19, CD185 and HLA-DR is reduced. In contrast to human GrB+ B cells, we did not observe a significantly increased expression of CD43 and CD86. B-cell receptor stimulation in combination with IL-21 of purified B cells from healthy animals led to the induction of GrB expression. Furthermore, initial functional analyses indicated a regulatory role on T-cell proliferation. Overall, our data pave the way for longitudinal analyses including studies on the functionality of GrB+ B cells in the nonhuman primate model for AIDS.Immunology and Cell Biology advance online publication, 25 October 2016; doi:10.1038/icb.2016.96. © 2016 The Author(s)
Dammhahn M.,Leibniz Institute for Primate Research |
Almeling L.,Leibniz Institute for Primate Research
Animal Behaviour | Year: 2012
During foraging, animals have to balance the risk of predation with the energy gain. The amount of risk animals take for a given resource depends on their energy budget but is expected also to vary between individuals of different personality types. We tested whether individuals of free-ranging grey mouse lemurs, Microcebus murinus, forage risk-sensitively and are consistent in their risk-taking behaviour. Furthermore, we tested whether boldness towards a novel object predicts risk taking in a foraging task. In a field experiment, we simulated low and high predation risk at artificial feeding sites. During focal platform observations, we quantified behaviours related to exploration and feeding for 36 individuals. Furthermore, we used a novel object test to quantify variation in boldness for 22 of these individuals. As predicted, grey mouse lemurs foraged risk-sensitively indicated by longer latencies to enter a feeding platform and to start feeding as well as by relatively longer feeding time compared to nonfeeding in high-risk situations. Individual differences in risk taking were repeatable and repeatability increased with increasing risk. Individual plasticity was higher for low-risk individuals providing field evidence for coping styles. There was no relationship between individual body condition and risk-taking behaviour. Finally, boldness measured in a novel object test was correlated with risk taking in a foraging task, providing a rare ecological validation for this personality trait. These results suggest that intrinsic individual differences in boldness need to be considered as an important source of variation when testing predictions of risk-sensitive foraging using optimality approaches. © 2012 The Association for the Study of Animal Behaviour.
Dammhahn M.,Leibniz Institute for Primate Research
Proceedings. Biological sciences / The Royal Society | Year: 2012
Despite increasing interest, animal personality is still a puzzling phenomenon. Several theoretical models have been proposed to explain intraindividual consistency and interindividual variation in behaviour, which have been primarily supported by qualitative data and simulations. Using an empirical approach, I tested predictions of one main life-history hypothesis, which posits that consistent individual differences in behaviour are favoured by a trade-off between current and future reproduction. Data on life-history were collected for individuals of a natural population of grey mouse lemurs (Microcebus murinus). Using open-field and novel-object tests, I quantified variation in activity, exploration and boldness for 117 individuals over 3 years. I found systematic variation in boldness between individuals of different residual reproductive value. Young males with low current but high expected future fitness were less bold than older males with high current fecundity, and males might increase in boldness with age. Females have low variation in assets and in boldness with age. Body condition was not related to boldness and only explained marginal variation in exploration. Overall, these data indicate that a trade-off between current and future reproduction might maintain personality variation in mouse lemurs, and thus provide empirical support of this life-history trade-off hypothesis.
Vuarin P.,CNRS Mechanical Adaptation and Evolution |
Dammhahn M.,Leibniz Institute for Primate Research |
Henry P.-Y.,CNRS Mechanical Adaptation and Evolution
Functional Ecology | Year: 2013
Phenotypic flexibility is a major mechanism in compensating climate-driven changes in resource availability. Heterotherms can use daily torpor to overcome resource shortages and adverse environmental conditions. The expression of this adaptive energy-saving strategy varies among individuals, but the factors constraining individual flexibility remain largely unknown. As energy availability depends on individual stores and/or on the ability to acquire food, the propensity and flexibility in torpor use are expected to be constrained by body condition and/or size, respectively. The aim of this study was to test whether the dependency of torpor depth on air temperature was constrained by body condition and/or body size in a small heterothermic primate, the grey mouse lemur (Microcebus murinus). During the onset of the dry season, we monitored air temperature as well as skin temperatures of 14 free-ranging individuals (12 females, two males) of known body mass and size. Unexpectedly, torpor depth depended as much on air temperature as on body condition and size. Fatter, or larger, mouse lemurs underwent deeper torpor than smaller, or leaner, ones. Individual reaction norms of torpor depth to air temperature also revealed that the propensity to undergo deep torpor and the flexibility in torpor depth were enhanced by large body size and high body condition, whereas small, lean individuals remained normothermic. Our study illustrates that alternative physiological strategies to overcome temperature constraints co-occur in a population, with body size and condition being key determinants of the energy conservation strategy that an individual can launch. © 2013 The Authors. Functional Ecology © 2013 British Ecological Society.
Brameier M.,Leibniz Institute for Primate Research
BMC Research Notes | Year: 2010
Background. MicroRNAs (miRNAs) are negative regulators of gene expression in multicellular eukaryotes. With the recently completed sequencing of three primate genomes, the study of miRNA evolution within the primate lineage has only begun and may be expected to provide the genetic and molecular explanations for many phenotypic differences between human and non-human primates. Findings. We scanned all three genomes of non-human primates, including chimpanzee (Pan troglodytes), orangutan (Pongo pygmaeus), and rhesus monkey (Macaca mulatta), for homologs of human miRNA genes. Besides sequence homology analysis, our comparative method relies on various postprocessing filters to verify other features of miRNAs, including, in particular, their precursor structure or their occurrence (prediction) in other primate genomes. Our study allows direct comparisons between the different species in terms of their miRNA repertoire, their evolutionary distance to human, the effects of filters, as well as the identification of common and species-specific miRNAs in the primate lineage. More than 500 novel putative miRNA genes have been discovered in orangutan that show at least 85 percent identity in precursor sequence. Only about 40 percent are found to be 100 percent identical with their human ortholog. Conclusion. Homologs of human precursor miRNAs with perfect or near-perfect sequence identity may be considered to be likely functional in other primates. The computational identification of homologs with less similar sequence, instead, requires further evidence to be provided. © 2010 Brameier; licensee BioMed Central Ltd.