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1.
Proc Biol Sci ; 287(1931): 20201079, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32693726

RESUMO

The biological clock expresses circadian rhythms, whose endogenous period (tau) is close to 24 h. Daily resetting of the circadian clock to the 24 h natural photoperiod might induce marginal costs that would accumulate over time and forward affect fitness. It was proposed as the circadian resonance theory. For the first time, we aimed to evaluate these physiological and cognitive costs that would partially explain the mechanisms of the circadian resonance hypothesis. We evaluated the potential costs of imposing a 26 h photoperiodic regimen compared to the classical 24 h entrainment measuring several physiological and cognitive parameters (body temperature, energetic expenditure, oxidative stress, cognitive performances) in males of a non-human primate (Microcebus murinus), a nocturnal species whose endogenous period is about 23.5 h. We found significant higher resting body temperature and energy expenditure and lower cognitive performances when the photoperiodic cycle length was 26 h. Together these results suggest that a great deviation of external cycles from tau leads to daily greater energetic expenditure, and lower cognitive capacities. To our knowledge, this study is the first to highlight potential mechanisms of circadian resonance theory.


Assuntos
Cheirogaleidae/fisiologia , Ritmo Circadiano , Animais , Temperatura Corporal , Relógios Circadianos , Cognição , Masculino , Atividade Motora , Fotoperíodo , Vibração
2.
Hist Philos Life Sci ; 42(2): 26, 2020 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-32529381

RESUMO

In the early 1990s, Microcebus murinus, a small primate endemic to Madagascar, emerged as a potential animal model for the study of aging and Alzheimer's disease. This paper traces the use of the lesser mouse lemur in research on aging and associated neurodegenerative diseases, focusing on a basic material precondition that made this possible, namely, the conversion of a wild animal into an experimental organism that lives, breeds, and survives in the laboratory. It argues that the "old" mouse lemur model can be considered as an eco-zootechnical acquisition. This is shown by examining how, since the early 1970s, French mouse lemur researchers have articulated colony productivity and viability with the influence of environmental factors on the demographics and physiology of the species. The appearance and maintenance of a growing number of old mouse lemurs in French research facilities are related to three developments: the application of the ecological notion of "social stress" to the understanding and management of the behavior of the captive population; the experimental demonstration that a variety of seasonal physiological changes in the species were influenced by the photoperiod; and the related attempt to accelerate aging in mouse lemurs through the manipulation of annual light conditions.


Assuntos
Envelhecimento , Cheirogaleidae/fisiologia , Modelos Animais , Animais , Modelos Animais de Doenças , Doenças Neurodegenerativas/patologia , Doenças Neurodegenerativas/fisiopatologia
3.
Biochim Biophys Acta Gene Regul Mech ; 1863(1): 194473, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31837470

RESUMO

When food scarcity is coupled with decreased temperatures, gray mouse lemurs (Microcebus murinus) depress their metabolic rates and retreat into bouts of either daily torpor or multi-day hibernation, without dramatically dropping body temperatures like other 'traditional hibernators'. Rapid and reversible mechanisms are required to coordinate the simultaneous suppression of energetically expensive processes and activation of pro-survival pathways critical for successful torpor-arousal cycling. MicroRNAs, a class of endogenous non-coding small RNAs, are effective post-transcriptional regulators that modulate all aspects of cellular function. The present study hypothesizes that miRNAs are intimately involved in facilitating the molecular reorganization events necessary for lemur skeletal muscle torpor. Small RNA-Sequencing was used to compare miRNA profiles from skeletal muscles of torpid and control primates. We characterized 234 conserved miRNAs, of which 20 were differentially expressed during torpor, relative to control. Examples included downregulation of key muscle-specific (myomiR) members, miR-1 and miR-133, suggesting a switch to muscle-specific energy-saving strategies. In silico target mapping and logistic regression-based gene set analysis indicated the inhibition of energy costly pathways such as oxidative phosphorylation and muscle proliferation. The suppression of these metabolic pathways was balanced with a lack of miRNA inhibition of various signaling pathways, such as MAPK, mTOR, focal adhesion, and ErbB. This study identifies unique miRNA signatures and 'biomarkers of torpor' that provide us with primate-specific insights on torpor at high body temperatures that can be exploited for human biomedical concerns.


Assuntos
Cheirogaleidae/genética , MicroRNAs/metabolismo , Músculo Esquelético/metabolismo , Torpor/genética , Animais , Cheirogaleidae/metabolismo , Análise por Conglomerados , Regulação para Baixo , Regulação da Expressão Gênica , RNA-Seq , Reação em Cadeia da Polimerase em Tempo Real
4.
Folia Primatol (Basel) ; 90(5): 361-378, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31416068

RESUMO

It has been proposed that primates use advertisement calls exclusively to negotiate spacing, but the function of female calls has rarely been studied. Here, we investigated the function of male and female advertisement calls in the northern giant mouse lemur (Mirza zaza),a non-gregarious nocturnal primate from north-western Madagascar. We recorded advertisement calls and associated behaviours of 35 M. zaza individuals at the Duke University Lemur Center. We found that females of M. zazaexclusively use their advertisement calls to advertise oestrus. In contrast, male advertisement calls appeared to be used in a spacing context. These findings show that primates can use their advertisement calls for both spacing and mate attraction, and that the sexes may differ in how they use these calls. The novel find of females of M. zazaattracting mates with loud advertisement calls contrasts with many non-primate taxa, where acoustic mate attraction is usually a function of male advertisement calls, and with other primates, where females use visual and olfactory cues to attract males. The loud female advertisement calls of M. zaza likely ensure mating success during the short receptive phase in this non-gregariously foraging, nocturnal primate.


Assuntos
Cheirogaleidae/fisiologia , Comportamento Sexual Animal , Territorialidade , Vocalização Animal , Animais , Feminino , Madagáscar , Masculino
5.
Syst Parasitol ; 96(8): 703-713, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31452131

RESUMO

A new chigger mite species, Schoutedenichia microcebi n. sp. is described from the grey mouse lemur Microcebus murinus (J.F. Miller) from Madagascar. The new species is closely related to S. dutoiti (Radford, 1948), a species described from a single specimen collected on a rodent in South Africa. Examination of the holotype and new material on S. dutoiti from South Africa enabled us to re-describe this species and provide new data on its hosts and geographical distribution.


Assuntos
Cheirogaleidae/parasitologia , Trombiculidae/classificação , Trombiculidae/fisiologia , Animais , Madagáscar , Camundongos , África do Sul , Especificidade da Espécie
7.
BMC Ecol ; 19(1): 20, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101046

RESUMO

BACKGROUND: Social tolerance strongly influences the patterns of affiliation and aggression in animal societies. However, not much is known about the variation of social tolerance in species living in dispersed social systems that combine solitary foraging activities with the need of coordinating social interactions with conspecifics on a regular basis. This study aims to investigate the sources of variation in social tolerance within a Malagasy primate radiation with dispersed social systems, the mouse lemurs (Microcebus spp.). Six mouse lemur species were selected as model species that belong to three different taxonomic clades, live in two types of forest environments (dry and humid), and differed in this study with respect to their reproductive activity. Six male-female and six male-male dyads of each species were tested temporarily in a standardized social encounter paradigm in Madagascar to collect data on joint use of space, non-agonistic body contacts, aggression rates, the number of conflicts and the establishment of intra- and intersexual dominance. RESULTS: Male-female dyads of the six species differed significantly in the frequency of affiliative and agonistic behaviors. In contrast, the variations between male-male dyads could not be explained by one parameter only, but clade membership, forest type, reproductive state as well as species were all suggested to be partially influential. Only one species (Microcebus mamiratra) showed signals of unambiguous female dominance in all male-female dyads, whereas the others had no or only a few dyads with female dominance. CONCLUSIONS: Variations in social tolerance and its consequences are most likely influenced by two factors, ecology (via forest type) and physiology (via reproductive activity), and only to a lesser extent by clade membership. The study suggests that mouse lemur females have higher aggression rates and more agonistic conflicts with males when females in the population are reproducing, at least in resource-rich humid forests. The study confirms a high degree of social plasticity between species in these small solitary foragers that supports their taxonomic distinctiveness and requires further scientific attention.


Assuntos
Cheirogaleidae , Animais , Feminino , Madagáscar , Masculino , Camundongos , Reprodução
8.
Neuroimage ; 185: 85-95, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30326295

RESUMO

The gray mouse lemur (Microcebus murinus) is a small prosimian of growing interest for studies of primate biology and evolution, and notably as a model organism of brain aging. As brain atlases are essential tools for brain investigation, the objective of the current work was to create the first 3D digital atlas of the mouse lemur brain. For this, a template image was constructed from in vivo magnetic resonance imaging (MRI) data of 34 animals. This template was then manually segmented into 40 cortical, 74 subcortical and 6 cerebro-spinal fluid (CSF) regions. Additionally, we generated probability maps of gray matter, white matter and CSF. The template, manual segmentation and probability maps, as well as imaging tools used to create and manipulate the template, can all be freely downloaded. The atlas was first used to automatically assess regional age-associated cerebral atrophy in a cohort of mouse lemurs previously studied by voxel based morphometry (VBM). Results based on the atlas were in good agreement with the VBM ones, showing age-associated atrophy in the same brain regions such as the insular, parietal or occipital cortices as well as the thalamus or hypothalamus. The atlas was also used as a tool for comparative neuroanatomy. To begin with, we compared measurements of brain regions in our MRI data with histology-based measures from a reference article largely used in previous comparative neuroanatomy studies. We found large discrepancies between our MRI-based data and those of the reference histology-based article. Next, regional brain volumes were compared amongst the mouse lemur and several other mammalian species where high quality volumetric MRI brain atlases were available, including rodents (mouse, rat) and primates (marmoset, macaque, and human). Unlike those based on histological atlases, measures from MRI atlases indicated similar cortical to cerebral volume indices in all primates, including in mouse lemurs, and lower values in mice. On the other hand, white matter to cerebral volume index increased from rodents to small primates (mouse lemurs and marmosets) to macaque, reaching their highest values in humans.


Assuntos
Atlas como Assunto , Encéfalo/anatomia & histologia , Cheirogaleidae/anatomia & histologia , Imageamento Tridimensional/métodos , Envelhecimento , Anatomia Comparada , Animais , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética , Masculino
9.
PLoS One ; 13(12): e0209640, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30576370

RESUMO

Within current theories on potential adaptive manipulation of offspring sex ratio, giving birth to a male or to a female is assumed to depend on the capacity of the mother to invest in offspring to maximize her fitness. The active role of the father in sex ratio bias at birth has been neglected until recently. The human sex ratio at birth is biased towards sons, although in occidental populations, the ratio has decreased regularly for 30 years and could be the consequence of the adverse effects of environmental chemicals on male hormones. In a Malagasy primate, the lesser mouse lemur, the potential effect of paternal testosterone levels on sex ratio bias at birth was tested on 130 litters (278 babies) produced in 52 mixed-sex groups. For each group, social dominance among males was characterized based on aggressive interactions and sexual behaviours. Using a multi correspondence analysis, high testosterone levels in grouped males, particularly those of the dominant male, were significantly correlated with more infants produced in male-biased litters, independent of the female condition. According to these results, predictions for sex ratio bias towards one sex or the other in mouse lemurs were discussed considering the influence of both parents.


Assuntos
Reprodução/fisiologia , Razão de Masculinidade , Sexismo , Comportamento Sexual/fisiologia , Animais , Cheirogaleidae , Feminino , Humanos , Masculino , Mães , Reprodução/genética
10.
Comp Med ; 68(6): 489-495, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30486920

RESUMO

Here we report a case of severe growth retardation and neurologic abnormalities in a female gray mouse lemur (Microcebus murinus), a small NHP species for which the genomic sequence recently became available. The female lemur we present here died on postnatal day 125. This lemur had impaired development of motor skills and showed severe ataxia and tremors. In addition, hearing seemed normal whereas ophthalmic examination revealed incipient bilateral cataracts, abnormal pigmentation in the lens of the left eye, and a missing optokinetic nystagmus, which indicated impaired vision. Most prominently, the lemur showed severe growth retardation. Necropsy revealed maldevelopment of the left reproductive organs and unilateral dilation of the right lateral ventricle, which was confirmed on brain MRI. Brain histology further revealed large, bilateral areas of vacuolation within the brainstem, but immunohistochemistry indicated no sign of pathologic prion protein deposition. Full genomic sequencing of the lemur revealed a probably pathologic mutation in LARGE2 of the LARGE gene family, which has been associated with congenital muscular dystrophies. However, potentially functional mutations in other genes were also present. The observed behavioral and motor signs in the presented animal might have been linked to spongiform degeneration and resulting brainstem dysfunction and progressive muscle weakness. The macroscopic developmental abnormalities and ophthalmic findings might be genetic in origin and linked to the mutation in LARGE2.


Assuntos
Cheirogaleidae/crescimento & desenvolvimento , Transtornos do Crescimento/veterinária , Doenças Neurodegenerativas/veterinária , Doenças dos Primatas/patologia , Síndrome de Walker-Warburg/veterinária , Animais , Comportamento Animal , Tronco Encefálico/patologia , Cheirogaleidae/anatomia & histologia , Cheirogaleidae/genética , Olho/patologia , Feminino , Transtornos do Crescimento/patologia , Doenças Neurodegenerativas/patologia , Síndrome de Walker-Warburg/genética , Síndrome de Walker-Warburg/patologia
11.
J Comp Psychol ; 132(3): 306-314, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30080072

RESUMO

Apes and some New and Old World monkeys (i.e., haplorhine primates) are known to routinely use tools. In strepsirrhine primates (i.e., lemurs and lorises), no tool use has been reported, even though they appear to have some basic understanding of the spatial relations required for using a pulling tool. To facilitate direct comparisons of the underlying abilities between haplorhine and strepsirrhine primate species, we experimentally examined instrumental problem-solving abilities in three captive lemur species (Microcebus murinus, Varecia variegata, and Lemur catta), using methods from previous experiments with haplorhine primates. First, lemurs were supposed to use a stick to gain access to an inaccessible food reward. Only one ring-tailed lemur solved this task spontaneously on the first attempt. After offering the stick repeatedly, 13 individuals of all three species solved it successfully. Second, lemurs had to choose between pairs of reachable objects with a food reward on or near them, where one object did not afford pulling in the food. Ring-tailed and gray mouse lemurs generally selected the correct (connected) object, thus performing comparably with haplorhine primates, and ruffed lemurs even matched chimpanzees in their performance. Thus, although strepsirrhine primates may lack the fine motor skills to use a stick as a reaching tool, they performed comparable with naturally tool-using haplorhine primates on means-end problems. Our findings suggest a dissociation in primates between the judgment of spatial relations between two objects, which appears to be roughly equivalent across species, and facility at handling sticks for instrumental purposes, which favors species with enhanced manual dexterity. (PsycINFO Database Record


Assuntos
Cheirogaleidae , Alimentos , Lemur , Resolução de Problemas , Recompensa , Animais , Comportamento Social , Especificidade da Espécie
12.
Bioessays ; 40(10): e1800111, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30067295

RESUMO

The effects of calorie restriction have now been studied in two non-human primates, the macaque Macaca mulatta and the mouse lemur Microcebus murinus. The study on lemurs and one of the two studies on macaques have reported a lifespan increase. In this review, I argue that these results are better explained by a lifespan decrease in the control group because of a bad diet and/or overfeeding, rather than by a real lifespan increase in calorie-restricted animals. If these results can be readily translated to humans, it would mean that no beneficial effect of calorie restriction on lifespan can be expected in normal-weight or lean people, but that overweight and/or obese people could benefit to some extent from a decrease in excessive food intake.


Assuntos
Restrição Calórica , Cheirogaleidae/fisiologia , Longevidade/fisiologia , Macaca mulatta/fisiologia , Animais , Estudos de Casos e Controles , Humanos , Sobrepeso/dietoterapia
13.
Artigo em Inglês | MEDLINE | ID: mdl-30104438

RESUMO

Linking the cognitive performance of wild animals with fitness consequences is crucial for understanding evolutionary processes that shape individual variation in cognition. However, the few studies that have examined these links revealed differing relationships between various cognitive performance measures and fitness proxies. To contribute additional comparative data to this body of research, we linked individual performance during repeated problem-solving and spatial learning ability in a maze with body condition and survival in wild grey mouse lemurs (Microcebus murinus). All four variables exhibited substantial inter-individual variation. Solving efficiency in the problem-solving task, but not spatial learning performance, predicted the magnitude of change in body condition after the harsh dry season, indicating that the ability to quickly apply a newly discovered motor technique might also facilitate exploitation of new, natural food resources. Survival was not linked with performance in both tasks, however, suggesting that mouse lemurs' survival might not depend on the cognitive performances addressed here. Our study is the first linking cognition with fitness proxies in a wild primate species, and our discussion highlights the importance and challenges of accounting for a species' life history and ecology in choosing meaningful cognitive and fitness variables for a study in the wild.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.


Assuntos
Cheirogaleidae/genética , Cheirogaleidae/psicologia , Cognição , Aptidão Genética , Resolução de Problemas , Aprendizagem Espacial , Animais , Variação Biológica Individual , Feminino , Longevidade , Masculino , Aprendizagem em Labirinto
14.
Gene ; 677: 332-339, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30103007

RESUMO

MicroRNA (miRNA) are endogenous small noncoding RNA gene products, on average 22 nt long, that play important regulatory roles in mediating gene expression by binding to and targeting mRNAs for degradation or translational repression. In this paper we identify both novel and conserved miRNA sequences present in the genome of the gray mouse lemur, Microcebus marinus. In total, 122 conserved and 44 novel miRNA were identified with high confidence from the lemur genome (Mmur_2.0) and were used for expression analysis. All conserved and novel miRNA were subjected to relative quantification by RT-qPCR in liver samples from control and torpid lemurs. A total of 26 miRNA (16 conserved and 10 novel) showed increased levels during primate torpor, whereas 31 (30 conserved and 1 novel) decreased. Additional in silico mapping of the predicted mRNA targets of torpor-responsive mature miRNA suggested that miRNA that increased during torpor were collectively involved in cell development and survival pathways, while miRNA that decreased were enriched in targeting immune function. Overall, the study suggests new regulatory mechanisms of primate torpor via miRNA action.


Assuntos
Cheirogaleidae/genética , Sequência Conservada/genética , Lemur/genética , MicroRNAs/genética , Torpor/genética , Animais , Fígado/metabolismo , Biossíntese de Proteínas/genética , RNA Mensageiro/genética
15.
Parasit Vectors ; 11(1): 459, 2018 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-30089527

RESUMO

BACKGROUND: Ectoparasitic infections are of particular interest for endangered wildlife, as ectoparasites are potential vectors for inter- and intraspecific pathogen transmission and may be indicators to assess the health status of endangered populations. Here, ectoparasite dynamics in sympatric populations of two Malagasy mouse lemur species, Microcebus murinus and M. ravelobensis, were investigated over an 11-month period. Furthermore, the animals' body mass was determined as an indicator of body condition, reflecting seasonal and environmental challenges. Living in sympatry, the two study species experience the same environmental conditions, but show distinct differences in socioecology: Microcebus murinus sleeps in tree holes, either solitarily (males) or sometimes in groups (females only), whereas M. ravelobensis sleeps in mixed-sex groups in more open vegetation. RESULTS: Both mouse lemur species hosted ticks (Haemaphysalis sp.), lice (Lemurpediculus sp.) and mites (Trombiculidae gen. sp. and Laelaptidae gen. sp.). Host species, as well as temporal variations (month and year), were identified as the main factors influencing infestation. Tick infestation peaked in the late dry season and was significantly more often observed in M. murinus (P = 0.011), while lice infestation was more likely in M. ravelobensis (P < 0.001) and showed a continuous increase over the course of the dry season. Genetic analyses identified Lemurpediculus sp. infesting both mouse lemur species. Ticks morphologically conform to H. lemuris, but genetic analysis showed a clear differentiation of the specimens collected in this study, suggesting a potentially new tick species. Host body mass decreased from the early to the late dry season, indicating nutritional stress during this period, which may render individuals more susceptible to parasitic infections. CONCLUSIONS: Seasonal differences and species-specific variations in sleeping site ecology in terms of sleeping site type and sociality were determined as key factors influencing ectoparasitism in M. murinus and M. ravelobensis. This needs to be taken into account when evaluating ectoparasite infestations at a given time point. The detection of the same parasite species on two closely related and sympatric host species furthermore indicates a potential pathway for disease transmission, not only within but also between lemur species.


Assuntos
Cheirogaleidae/parasitologia , Infestações por Piolhos/veterinária , Infestações por Ácaros/veterinária , Infestações por Carrapato/veterinária , Distribuição Animal , Animais , Comportamento Animal , Feminino , Infestações por Piolhos/epidemiologia , Madagáscar/epidemiologia , Masculino , Infestações por Ácaros/epidemiologia , Estações do Ano , Comportamento Social , Especificidade da Espécie , Infestações por Carrapato/epidemiologia , Fatores de Tempo
16.
JCI Insight ; 3(14)2018 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-30046008

RESUMO

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease among the elderly. To understand its pathogenesis and to test therapies, animal models that faithfully reproduce key pathological PD hallmarks are needed. As a prelude to developing a model of PD, we tested the tropism, efficacy, biodistribution, and transcriptional effect of canine adenovirus type 2 (CAV-2) vectors in the brain of Microcebus murinus, a nonhuman primate that naturally develops neurodegenerative lesions. We show that introducing helper-dependent (HD) CAV-2 vectors results in long-term, neuron-specific expression at the injection site and in afferent nuclei. Although HD CAV-2 vector injection induced a modest transcriptional response, no significant adaptive immune response was generated. We then generated and tested HD CAV-2 vectors expressing leucine-rich repeat kinase 2 (LRRK2) and LRRK2 carrying a G2019S mutation (LRRK2G2019S), which is linked to sporadic and familial autosomal dominant forms of PD. We show that HD-LRRK2G2019S expression induced parkinsonian-like motor symptoms and histological features in less than 4 months.


Assuntos
Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/metabolismo , Serina-Treonina Proteína Quinase-2 com Repetições Ricas em Leucina/farmacologia , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Adenovirus Caninos/genética , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Cheirogaleidae , Feminino , Perfilação da Expressão Gênica , Vetores Genéticos , Masculino , Mutação , Neurônios/efeitos dos fármacos , Técnicas Estereotáxicas , Distribuição Tecidual , Transcriptoma , Transdução Genética , Tropismo
17.
Primates ; 59(4): 355-360, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29882030

RESUMO

Fork-marked dwarf lemurs (Phaner spp.) of Madagascar and the needle-clawed galagos (Euoticus spp.) of Central-West Africa are two genera within the primate suborder Strepsirrhini. Despite their distant relationship, these genera share remarkably convergent anatomical, behavioural and ecological characteristics. However, like most nocturnal primates in sub-Saharan Africa they are poorly studied and little is known about the population estimates of both genera. I conducted surveys of wild populations of Phaner pallescens, P. parienti and P. furcifer in Madagascar as well as Euoticus elegantulus and E. pallidus in Cameroon. Six transects were established in Madagascar covering a total distance of 20 km, within which I encountered 52 fork-marked dwarf lemurs. In Cameroon three transects were established covering a total distance of 8.5 km, and 56 encounters of needle-clawed galagos were made. Population encounter rates of P. pallescens, P. parienti, P. furcifer, E. elegantulus and E. pallidus were 3.3, 2.4, 2.3, 9.9 and 8.3 individuals per kilometre, respectively. Compared to previous estimates of population encounter rates in other study sites, these values are lower. Low population encounter rates of fork-marked dwarf lemurs and needle-clawed galagos may be due to environmental and anthropogenic pressures at the study sites. Further ecological, behavioural and conservation studies are required for these genera.


Assuntos
Cheirogaleidae , Galago , Densidade Demográfica , Animais , Camarões , Madagáscar
18.
Am J Primatol ; 80(7): e22874, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29767414

RESUMO

Reproduction is a fundamental trait in the life history of any species and contributes to species diversity and evolution. Here, we aim to review the barely known variation in reproductive patterns of the smallest-bodied primate radiation, the Malagasy mouse lemurs, focusing on twelve species of four phylogenetic clades. We present a new reproductive field dataset collected between May and November 1996-2016 for nine species (Microcebus murinus, M. myoxinus, M. ravelobensis, M. bongolavensis, M. danfossi, M. sambiranensis, M. margothmarshae, M. mamiratra, and M. lehilahytsara) and add published field information on three additional species. In the majority of species, the estrus of females was recorded in the period of long days (day length longer than 12 hr), whereas male testes size increased about one to three months prior to this. Reproductive schedules varied considerably between the four clades. Sympatric species-pairs of different clades differed in the timing of female and male reproduction, suggesting strong phylogenetic constraints. Populations of the same species in a different ecological setting varied in the onset of reproduction, suggesting substantial environmental plasticity. Warm temperatures and rainfall throughout the year may allow for less expressed reproductive seasonality. Our results suggest that an interplay between phylogenetic relatedness, ambient temperature (as a proxy for thermo regulatory constraints), and rainfall (as a proxy for food availability), may best explain this variation. Findings further point to a more complex control of mouse lemur reproduction than previously described and illuminate phylogenetic constraints and adaptive potentials in behavioral reaction norms of a species-rich primate radiation.


Assuntos
Cheirogaleidae/fisiologia , Reprodução/fisiologia , Animais , Cheirogaleidae/classificação , Feminino , Madagáscar , Masculino , Ciclo Menstrual/fisiologia , Filogenia , Chuva , Estações do Ano , Temperatura , Testículo/fisiologia
19.
Am J Primatol ; 80(6): e22864, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29717507

RESUMO

Needle-clawed galagos (Euoticus spp.) and fork-marked dwarf lemurs (Phaner spp.) are specialist gummivores inhabiting the forests of Cameroon and Madagascar, respectively. They share a suite of adaptations related to their foraging behavior, but are distantly related. I compared structural characteristics of the natural vegetation in which these strepsirrhines occurred using 10 m × 10 m (100 m2 ) quadrats established in forest areas selected on the grounds of observations of animals during nocturnal surveys. I established a total of 27 quadrats (13 in Madagascar and 14 in Cameroon). In each quadrat, trees potentially used by the animals (i.e., with a circumference at breast height ≥10 cm) were assessed for diameter at breast height (DBH), total height, and maximum crown diameter (MCD) as well as tree density. The nature of the bark, and presence of exudates and flowers were also assessed, together with habitat characteristics such as percentage canopy cover and herbaceous cover. Primary and secondary forest types studied in Madagascar showed significant differences in DBH, MCD, and tree density, whereas only tree density was significantly different for the two forest types in Cameroon. Most of the trees in the quadrats had rough bark, but few had either exudates or flowers. Both Phaner and Euoticus show some degree of plasticity in their use of both primary and secondary forests, although they specialize in habitats with tall, large diameter trees. They can adjust to using trees in human modified habitats. Both taxa can survive in areas where a reasonably continuous canopy is not lacking.


Assuntos
Cheirogaleidae , Ecossistema , Galago , Animais , Camarões , Flores , Florestas , Madagáscar , Casca de Planta , Árvores/classificação
20.
Am J Primatol ; 80(6): e22866, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29722032

RESUMO

The critically endangered Claire's mouse lemur, only found in the evergreen rain forest of the National Park Lokobe (LNP) and a few lowland evergreen rain forest fragments of northern Madagascar, was described recently. The present study provides the first quantified information on vocal acoustics of calls, sound associated behavioral context, acoustic niche, and vocal activity of this species. We recorded vocal and social behavior of six male-female and six male-male dyads in a standardized social-encounter paradigm in June and July 2016 at the LNP, Nosy Bé island. Over six successive nights per dyad, we audio recorded and observed behaviors for 3 hr at the beginning of the activity period. Based on the visual inspection of spectrograms and standardized multiparametric sound analysis, we identified seven different call types. Call types can be discriminated based on a combination of harmonicity, fundamental frequency variation, call duration, and degree of tonality. Acoustic features of tonal call types showed that for communication, mouse lemurs use the cryptic, high frequency/ultrasonic frequency niche. Two call types, the Tsak and the Grunt call, were emitted most frequently. Significant differences in vocal activity of the Tsak call were found between male-female and male-male dyads, linked primarily to agonistic conflicts. Dominant mouse lemurs vocalized more than subdominant ones, suggesting that signaling may present an honest indicator of fitness. A comparison of our findings of the Claire's mouse lemur with published findings of five bioacoustically studied mouse lemur species points to the notion that a complex interplay between ecology, predation pressure, and phylogenetic relatedness may shape the evolution of acoustic divergence between species in this smallest-bodied primate radiation. Thus, comparative bioacoustic studies, using standardized procedures, are promising to unravel the role of vocalization for primate species diversity and evolution and for identifying candidates for vocalization-based non-invasive monitoring for conservation purposes.


Assuntos
Cheirogaleidae/fisiologia , Vocalização Animal/fisiologia , Animais , Espécies em Perigo de Extinção , Feminino , Madagáscar , Masculino , Predomínio Social , Espectrografia do Som , Ondas Ultrassônicas
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