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Copyright of International Journal of Primatology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present the first open-access, island-wide isotopic database (IsoMad) for modern biologically relevant materials collected on Madagascar within the past 150 years from both terrestrial and nearshore marine environments. Isotopic research on the island has increasingly helped with biological studies of endemic organisms, including evaluating foraging niches and investigating factors that affect the spatial distribution and abundance of species. The IsoMad database should facilitate future work by making it easy for researchers to access existing data (even for those who are relatively unfamiliar with the literature) and identify both research gaps and opportunities for using various isotope systems to answer research questions. We also hope that this database will encourage full data reporting in future publications. [ABSTRACT FROM AUTHOR]

Species can either maintain a certain social organization in different habitats or show different social organizations in similar habitats. The reasons underlying this variability are not always clear but might have consequences for population dynamics, especially under changing environmental conditions. Among mammals, the primate genus Microcebus lives in small groups of closely related females, derived from female philopatry and dispersed males, as illustrated by the well-studied Microcebus murinus. Here, we studied the genetic structure of a population of the congeneric Microcebus griseorufus, inhabiting three adjacent habitats with different resource availabilities. In order to learn more about the plasticity of the species' social organization under these different conditions, we analyzed the spatial arrangement of mitochondrial haplotypes of 122 individuals. The study revealed high haplotype diversity and a pronounced difference in spatial distribution between the sexes. Females exhibited spatial aggregation of haplotypes, suggesting a system of female philopatry and matrilines, similar to M. murinus. Male haplotypes were dispersed, and males were more likely to carry rare haplotypes, indicating higher dispersal activity. These findings hint towards the unity of the social organization across the genus Microcebus, suggesting a phylogenetic origin of the social organization. Yet, with decreasing resources, the clustering of female haplotypes declined and approached a random distribution in the marginal habitat, with cluster sizes correlating with resource availability as predicted by the socioecological model. Our study supports the notion that social organization is shaped by both phylogenetic origin and ecological conditions, at least in these small primates. Significance statement: Impacts of habitat degradation are mostly described in terms of changes in population densities in relation to the reduction of resources. This neglects the possible effects of altered social organizations due to declining resources or population densities. Using a genetic sampling of three subpopulations of mouse lemurs in Madagascar along a gradient of food availability up to the limit of the species' ecological tolerance, we show that their social organization consisting of spatial clusters of closely related females and overdispersed males converges towards random spatial distributions of both sexes with declining food availability. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Primatology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nature and species conservation often conflict with intensive natural resource or land use. Many protected areas are too small for long-term conservation of viable vertebrate populations, especially in Madagascar, and forests are subject to exploitation for a variety of natural resources. Trying to exclude people from the use of these resources has not been successful during economic, natural, or political crises or when human population growth outruns any development effort. People need economic and other benefits, and conservation measures have to account for these needs. We compiled native and introduced tree, shrub, and herbaceous species used by both people and native vertebrates for three regions, covering the domains of the dry, transitional, and humid forest of Madagascar. We carried out semistructured interviews and group discussions in 12 different villages in each study region in November 2017. People listed 139 utilitarian plant taxa. Our literature search revealed that 72 of these plant species and 13 genera used by people, were also used by 208 different terrestrial vertebrates including 58 lemur species. Application of the Forest Landscape Restoration approach with a combination of exotic and native plant species used by both people and animals could increase the economic value of restored forest habitats for people, thus providing incentives for forest conservation. Plantations of mixed utilitarian trees and shrubs could be integrated into agricultural landscapes. Among land-living vertebrates, lemurs seem to benefit most from this approach. These measures might contribute to a successful array of biodiversity conservation in anthropogenic landscapes. [ABSTRACT FROM AUTHOR]

Forest restoration is a prime goal within the 2021–2030 UN "Decade of Ecosystem Resoration". As part of these activities, natural regeneration has to be promoted for biological as well as for economic reasons. For this, the processes of seed dispersal, seed predation and germination have to be understood in the original as well as in degraded vegetation formations. We used seed removal experiments to assess post-dispersal processes that influence recruitment along a gradient of forest degradation in Madagascar analyzing seeds of three animal dispersed tree species. The percentage of seeds consumed or dispersed, declined from forest (28.6%) to degraded forest (17.2%) to savanna (10.8%). Only three out of 1080 seeds were cached and remained intact during the 14-day experiment. All three seeds were cached in the forest habitat and none in the degraded forest and savanna. The low percentage of seeds removed may be due to the lack of endemic rodents caching seeds, as only introduced rats were recorded in the area. The species-poor fauna of potential secondary seed dispersers of the region and especially in the degraded areas might represent an obstacle for diverse regeneration in degraded regions of Madagascar. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Experimental Biology & Medicine is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Flexibility in physiological processes is essential to adequately respond to changes in environmental conditions. Madagascar is a particularly challenging environment because climatic conditions seem less predictable than in comparative ecosystems in other parts of the world. We used the reddish-gray mouse lemur ( Microcebus griseorufus) from the most unpredictable environment in Madagascar as a model to investigate the flexibility of energy saving strategies to cope with the unpredictability of their habitat. For this we measured T of free-ranging mouse lemurs throughout the year using temperature data loggers. M. griseorufus showed a very strong seasonal as well as an individual flexibility in thermoregulation. During the rainy season all M. griseorufus remained normothermic. At the beginning of the dry season individuals started to exhibit different energy saving strategies: irregular short torpor bouts, regular daily torpor, prolonged torpor of a few days, and hibernation over several weeks. The accumulation of sufficient seasonal body fat was the crucial factor determining the thermal behavior of individuals. The observed intraspecific and sex independent variation in thermoregulatory patterns within one population inhabiting the same small geographical area is exceptional and gives M. griseorufus the ability to respond to current environmental as well as individual conditions. This thermal plasticity might be seen as a key to success and survival for M. griseorufus in an extremely unpredictable environment. [ABSTRACT FROM AUTHOR]

Very little is known about how nocturnal primates find their food. Here we studied the sensory basis of food perception in wild-caught gray mouse lemurs (Microcebus murinus) in Madagascar. Mouse lemurs feed primarily on fruit and arthropods. We established a set of behavioral experiments to assess food detection in wild-born, field-experienced mouse lemurs in short-term captivity. Specifically, we investigated whether they use visual, auditory, and motion cues to find and to localize prey arthropods and further whether olfactory cues are sufficient for finding fruit. Visual cues from motionless arthropod dummies were not sufficient to allow reliable detection of prey in choice experiments, nor did they trigger prey capture behavior when presented on the feeding platform. In contrast, visual motion cues from moving prey dummies attracted their attention. Behavioral observations and experiments with live and recorded insect rustling sounds indicated that the lemurs make use of prey-generated acoustic cues for foraging. Both visual motion cues and acoustic prey stimuli on their own were sufficient to trigger approach and capture behavior in the mouse lemurs. For the detection of fruit, choice experiments showed that olfactory information was sufficient for mouse lemurs to find a piece of banana. Our study provides the first experimental data on the sensory ecology of food detection in mouse lemurs. Further research is necessary to address the role of sensory ecology for food selection and possibly for niche differentiation between sympatric Microcebus species. [ABSTRACT FROM AUTHOR]

Gray mouse lemurs (Microcebus murinus) occur in western Madagascar from the evergreen littoral rain forests at the southern tip of the island to the seasonal dry deciduous forests of the west and northwest. The wide geographic distribution allows researchers to investigate whether ecogeographic variations reflect adaptations to ambient temperatures, as a proxy for constraints of thermoregulation, or to rainfall, as a proxy of food availability. We compared body mass, number of litters/yr, and longevity for 3 populations: 1 from the evergreen littoral rain forest of the south (Mandena: annual mean temperature 23°C, 1600 mm rain/yr), 1 from the dry deciduous forest of the west (Kirindy/CFPF: 25°C, 800 mm), and 1 from the dry deciduous forest of northwestern Madagascar (Ampijoroa: 27°C, 1200 mm). Body mass decreases with increasing ambient temperature from south to north (Mandena > Kirindy/CFPF > Ampijoroa). The number of litters/yr was highest in the littoral rain forest (2 or 3 litters/yr) and decreased with decreasing rainfall (Mandena > Ampijoroa > Kirindy/CFPF). Life expectancy is lowest in the littoral forest (13% recaptures of mouse lemurs between years) and high ( ca. 30–40% recaptures between years) in the dry forests (Mandena < Kirindy/CFPF and Ampijoroa). We postulate that constraints of thermoregulation result in the latitudinal gradient of body mass. Reduced resource productivity or seasonality is reflected in differences in reproductive rates, which seemed to be traded off against longevity. Thus body mass, longevity, and reproductive parameters respond differently to ambient conditions. [ABSTRACT FROM AUTHOR]

The Malagasy primateCheirogaleus mediushibernates in tree holes for 7 months, although ambient temperatures during hibernation rise above 30°C in their natural environment. In a field study we show that during hibernation the body temperature of most lemurs fluctuates between about 10°C and 30°C, closely tracking the diurnal fluctuations of ambient temperature passively. These lemurs do not interrupt hibernation by spontaneous arousals, previously thought to be obligatory for all mammalian hibernators. However, some lemurs hibernate in large trees, which provide better thermal insulation. Their body temperature fluctuates only little around 25°C, but they show regular arousals, as known from temperate and arctic hibernators. The results from this study demonstrate that maximum body temperature is a key factor necessitating the occurrence of arousals. Furthermore, we show that hibernation is not necessarily coupled to low body temperature and, therefore, low body temperature should no longer be included in the definition of hibernation. [ABSTRACT FROM AUTHOR]

We aimed to identify the geographical and biotic limitations of Microcebus berthae , the smallest extant primate. Furthermore we analyzed the mating system of two local populations and their habitat use in relation to microhabitat structures and to those of Microcebus murinus and Cheirogaleus medius , two potentially competing lemur species. The range of Microcebus berthae is restricted to ≤220 km[sup 2] in the dry deciduous forest of western Madagascar. A very optimistic estimate of the total population size is ca. 7900 individuals. During a 13-mo mark-recapture study individuals were trapped from May 1995 to May 1996 at permanent trap locations 50 m apart over 2 study areas of ca. 25 ha each. The spacing of trap locations where individuals have been retrapped indicate that males have larger home ranges than those of females, which in concert with multiple intra- and intersexual range overlap indicates a promiscuous mating system. In contrast to the other 2 species, Microcebus berthae maintained specific habitat utilization patterns at 2 sites with different vegetation structures. Their habitat use in relation to vegetation characteristics differed from that of Cheirogaleus medius but not from that of Microcebus murinus . Co-occurrence patterns of Microcebus berthae and M. murinus deviated significantly from random and resembled a checkerboard distribution possibly generated by competitive exclusion. Thus, according to the niche concept, Microcebus berthae seem to be separated from Cheirogaleus medius by differences in food composition and habitat requirements, while they avoid direct competition with M. murinus by spatial separation. [ABSTRACT FROM AUTHOR]

The geological history of Madagascar contains events that may have given rise to unusual factors that molded the primate communities of the island. In order to understand the impact of the factors we reviewed the elevational distribution of extant primate species in the humid forests. The elevational structuring of primates in the humid forests of Madagascar shows considerable differences from other tropical areas in the New World and Asia, which is correlated with the lack of large tracts of humid lowland habitat on Madagascar since it split from India. [ABSTRACT FROM AUTHOR]

We characterize the spatial organization of red-tailed sportive lemurs (Lepilemur ruficaudatus ) as a key aspect of their social organization and social system. Sportive lemurs are small (<1000 g), nocturnal and folivorous primates endemic to Madagascar. We studied a population of 57 individually-marked individuals in Kirindy Forest, western Madagascar, between 1995 and 2001. We radio-tracked 20 males and 26 females of the marked population to obtain detailed information on the size and location of their home ranges. Census data and morphometric measurements provided complementary data sets. Males and females occupied small (<1 ha) home-ranges. Long-term records from 9 individuals revealed home-range stability over several years. In 4 cases home ranges overlapped extensively with that of one member of the opposite sex; in 2 cases, a spatial association of 1 male and 2 females occurred. However, home ranges overlapped very little with neighboring individuals of both sexes. During the study period, spatially associated individuals used on average 5.6 sleeping trees within 117 days, but they spent on average only about every fourth night together. The data suggest that home ranges in red-tailed sportive lemurs are exclusively used by pairs or trios and that the modal social organization of red-tailed sportive lemurs is pair-living. [ABSTRACT FROM AUTHOR]

The goal of this study was to assess the relative importance of food availability and its quality for the spatial distribution of a folivorous lemur species, Lepilemur ruficaudatus, from the highly seasonal dry deciduous forest of Madagascar. Males and females of this species showed opposite changes of body mass and body condition during the dry and the wet season. Male body mass declined during the dry season that coincides with mating, while female body mass remained constant. During the wet season that coincides with lactation, female body mass declined but male body mass increased. This indicates that changes in body mass are not linked as much to environmental seasonality as to mating and reproduction. The distribution of L. ruficaudatus was most significantly related to the spatial distribution of leaf protein during the wet season. Neither the availability nor the chemical composition of leaves eaten during the dry season affected the spatial distribution of L. ruficaudatus. These findings are consistent with hypotheses that constraints are most severe during the times of lactation and weaning and that distributions of primates reflect their food requirements in order to optimize their reproductive success. They are inconsistent with the idea that the lean dry season is the most stressful time of year for lemurs in energetic or nutritive terms. [ABSTRACT FROM AUTHOR]

The genus Microcebus (mouse lemurs) are the smallest extant primates. Until recently, they were considered to comprise two different species: Microcebus murinus, confined largely to dry forests on the western portion of Madagascar, and M. rufus, occurring in humid forest formations of eastern Madagascar. Specimens and recent field observations document rufous individuals in the west. However, the current taxonomy is entangled due to a lack of comparative material to quantify intrapopulation and intraspecific morphological variation. On the basis of recently collected specimens of Microcebus from 12 localities in portions of western Madagascar, from Ankarana in the north to Beza Mahafaly in the south, we present a revision using external, cranial, and dental characters. We recognize seven species of Microcebus from western Madagascar. We name and describe 3 spp., resurrect a previously synonymized species, and amend diagnoses for Microcebus murinus (J. F. Miller, 1777), M. myoxinus Peters, 1852, and M. ravelobensis Zimmermann et al., 1998. [ABSTRACT FROM AUTHOR]

We studied the genetic differentiation of five populations of red-tailed sportive lemur Lepilemur ruficaudatus by means of allozyme variability and RAPD polymorphisms in order to test whether the Tsiribihina River separates the distribution areas of Lepilemur ruficaudatus and and L. edwardsi. Genetic data as well as the karyotype of a male individual clearly indicate that the Andramasay Forest in the north of Tsiribihina River is inhabited by Lepilemur ruficaudatus and not by L. edwardsi. We propose that the distribution of the two species are separated by the Manambolo River. However, the northernmost population of Lepilemur ruficaudatus inhabiting the Andramasay Forest is gentically differentiated from those that inhabit the dry forest in the south of Tsiribihina River. [ABSTRACT FROM AUTHOR]

The fat-tailed dwarf lemur ( Cheirogaleus medius; Cheirogaleidae) lives in the tropical forests of Madagascar. It is exceptional among primates, because this small nocturnal lemur hibernates during the dry season from the end of April until October. This field study was carried out to assess seasonal changes in body mass and behavioral traits (locomotor activity, feeding ecology) of C. medius that enable this species to accumulate large quantities of fat within weeks. Feeding observations of 36 radio-collared individuals were combined with a mark-recapture study in western Madagascar during the rainy seasons from 1995 to 1998. Pulp of fruit species not consumed, as well as fruit species eaten by C. medius was analyzed for lipid and sugar contents. Body mass changes of recaptured individuals revealed that C. medius may double its body mass within a few weeks. Most of the increase in body mass took place between March and April after infants had been weaned and directly before the onset of hibernation. Locomotor activity was significantly reduced during the period of body mass gain. During the entire study, fruits, nectar, and flowers of 34 different plant species comprised about 80% of the diet, supplemented by a seasonally varying intake of animal prey. Lipid contents of consumed fruits were comparatively low throughout the study period. No difference in lipid content was detectable between fruit species consumed and not consumed by C. medius. During prehibernation fattening, C. medius consumed mostly fruit species with a high sugar content, significantly higher than that of fruit species that were not consumed. The results suggest that a reduction in locomotor activity as well as a preference for fruit species with a high sugar content enable C. medius to deposit large quantities of fat in a few weeks. [ABSTRACT FROM AUTHOR]

The goal of this study was to identify causes for lower population densities of mouse lemurs (Microcebus murinus) in secondary than in primary dry deciduous forests of western Madagascar. Variations in the abundance of Microcebus murinus are linked to the capacity to enter energy-saving torpor during the dry season. Under natural conditions in primary forest, Microcebus murinus can maintain daily torpor (and possibly hibernation) as long as body temperatures remain below 28°C. Females are more likely to hibernate than males, resulting in skewed sex ratios of captured Microcebus murinus in the primary forest. In the secondary forest the sex ratio of subjects captured during the dry season is more balanced than in primary forest, indicating that fewer females go into torpor in secondary than in primary forest. Secondary forests have fewer large standing or fallen trees that might provide holes as shelter for Microcebus murinus. Ambient temperatures are higher in secondary than in primary forests and higher outside than inside tree holes. These high ambient temperatures might hinder the ability of Microcebus murinus to maintain torpor for prolonged periods in secondary forests. Mouse lemurs from secondary forest have lower body mass than in primary forest. The year-to-year recapture rate is zero in secondary forest and thus significantly lower than in primary forest. This indicates that survival rates are lower in secondary than in primary forests. Thus, secondary forests may be of limited value as buffer zones or even corridors for mouse lemurs. [ABSTRACT FROM AUTHOR]

Predictions of ecological models on female social relationships (van Schaik 1989) and their links with food distribution and the potential competitive regime are used to analyze the feeding and spatial behavior, and resource density, size, distribution, and quality in a forest population of Hanuman langurs ( Presbytis entellus). In contrast to other populations, and assumptions on folivorous primates, the females of this population exhibit a linear dominance hierarchy. The langurs concentrated their feeding on three key resources with a low density and clumped distribution. Two out of the three key resources contained significantly higher levels of extractable protein and soluble sugar than other food plants, indicating high spatial variability of food quality. Even the mature leaves of the most preferred food plant were about twice as nutritious as those from other food plants. Group spread was small and only a single high-quality resource was used at a time. Finally, even rich resources could accommodate only a subset of a group. These findings fit predictions made for the prevalence of within-group contest competition. Given the observed food distribution and phytochemical heterogeneity of mature foliage, even females of folivorous species should contest for food. The effect of female dominance rank on size and composition of feeding parties also agrees with this prediction. A comparison with data from another forest population, where female dominance relations are weakly developed, revealed a clear-cut difference in the use and abundance of resources. It is argued that between-population differences in female social relationships within a species may be viewed as adaptive responses to local habitat conditions. [ABSTRACT FROM AUTHOR]

Adenovirus (AdV) infections are one of the main causes of diarrhea in young children. Enteric AdVs probably disrupt gut microbial defences, which can result in diarrhea. To understand the role of the gut microbiome in AdV-induced pathologies, we investigated the gut microbiome of a naturally AdV-infected non-human primate species, the Malagasy mouse lemur (Microcebus griseorufus), which represents an important model in understanding the evolution of diseases. We observed that AdV infection is associated with disruption of the gut microbial community composition. In AdV+ lemurs, several commensal taxa essential for a healthy gut microbiome decreased, whereas genera containing potential pathogens, such as Neisseria, increased in abundance. Microbial co-occurrence networks revealed a loss of important microbial community interactions in AdV+ lemurs and an overrepresentation of Prevotellaceae. The observation of enteric virus-associated loss of commensal bacteria and associated shifts towards pathobionts may represent the missing link for a better understanding of AdV-induced effects in humans, and also for their potential as drivers of co-infections, an area of research that has been largely neglected so far. [ABSTRACT FROM AUTHOR]

The Madagascan fat-tailed dwarf lemur, Cheirogaleus medius, hibernates in tree holes for seven months of the year, even though winter temperatures rise to over 30 °C. Here we show that this tropical primate relies on a flexible thermal response that depends on the properties of its tree hole: if the hole is poorly insulated, body temperature fluctuates widely, passively following the ambient temperature; if well insulated, body temperature stays fairly constant and the animal undergoes regular spells of arousal. Our findings indicate that arousals are determined by maximum body temperatures and that hypometabolism in hibernating animals is not necessarily coupled to a low body temperature. [ABSTRACT FROM AUTHOR]