Blanchard Randrianambinina

Bio: Blanchard Randrianambinina is an academic researcher from University of Antananarivo. The author has contributed to research in topics: Lemur & Population. The author has an hindex of 4, co-authored 5 publications receiving 185 citations. Previous affiliations of Blanchard Randrianambinina include University of Veterinary Medicine Hanover.

Pair-specific usage of sleeping sites and their implications for social organization in a nocturnal Malagasy primate, the Milne Edwards' sportive lemur (Lepilemur edwardsi).

Abstract: Safe sleeping sites may be a limited resource crucial for survival. In order to investigate their potential significance for social organization in nocturnal primates, we analyzed the spatial distribution of daily sleeping sites, their characteristics, their usage, and sleeping group compositions in the nocturnal Milne Edwards' sportive lemur during a 6-month field study in the dry deciduous forest of northwestern Madagascar. Sexes did not differ either in body size or in body mass. Sleeping sites were used almost exclusively by adult male-female pairs. Individuals showed a high sleeping-site fidelity limited to 2-3 different sleeping sites in close vicinity during the whole study period. Most females showed a higher fidelity to one distinct sleeping site than their male partners. Sleeping groups consisted of one adult male and one adult female and remained stable in composition over the whole study period. Exclusive pair-specific usage of sleeping sites suggests sleeping site related territoriality of male-female pairs, perhaps influenced by inter- and intrasexual resource competition. Results give first insights into the distribution patterns and social organization of this species. They imply dispersed monogamy for the Milne Edwards' sportive lemur, with sleeping sites as a potentially restricted and defendable resource.

Seasonal changes in general activity, body mass and reproduction of two small nocturnal primates: a comparison of the golden brown mouse lemur ( Microcebus ravelobensis) in Northwestern Madagascar and the brown mouse lemur ( Microcebus rufus) in Eastern Madagascar.

Abstract: To investigate for the first time the relationship between contrasting patterns of seasonal changes of the environment and activity, body mass and reproduction for small nocturnal primates in nature, we compared a population of golden brown mouse lemur (Microcebus ravelobensis) in a dry deciduous forest of northwestern Madagascar and of the brown mouse lemur (Microcebus rufus) in an evergreen rain forest of eastern Madagascar. Both species live under similar photoperiodic conditions. Golden brown mouse lemurs (GBML) were active during the whole period (May to December) irrespective of changing environmental conditions. In contrast, a part of the population of brown mouse lemurs (BML) showed prolonged seasonal torpor, related to body mass during periods of short day length and low ambient temperatures. Differences between species might be due to differences in ambient temperature and food supply. Body weight and tail thickness (adipose tissue reserve) did not show prominent differences between short and long photoperiods in GBML, whereas both differ significantly in BML, suggesting species-specific differences in the photoperiodically driven control of metabolism. Both species showed a seasonal reproduction. The rate of growth and size of the testes were similar and preceded estrous onset in both species suggesting a photoperiodic control of reproduction in males. The estrous onset in females occurred earlier in GBML than in BML. Estrous females were observed over at least 4 months in the former, but in only 1 month in the latter species. Intraspecific variation of estrous onset in GBML may be explained by body mass. Interspecific variation of female reproduction indicates species-specific differences in the control of reproduction. Thus, environmentally related differences in annual rhythms between closely related small nocturnal lemurs emerged that allow them to cope with contrasting patterns of seasonal changes in their habitats.

Loud calling, spacing, and cohesiveness in a nocturnal primate, the Milne Edwards' sportive lemur (Lepilemur edwardsi)

Abstract: Dispersed pair-living primates provide a unique model for illuminating the evolution of mechanisms regulating spacing and cohesiveness in permanently cohesive groups. We present for the first time data on the spatiotemporal distribution and loud-calling behavior of the Milne Edwards' sportive lemur, known to forage solitarily during the night, but to form stable male-female sleeping groups during the day. Data include radio-tracking observations of sleeping associations, and focal follows of pair partners during dispersal in the evenings and reunions in the mornings. Male-female pairs forming stable sleeping associations during the day were pair-bonded. They used sleeping sites and home ranges exclusively, and exchanged loud calls at potentially restricted resources during dispersal in the evenings and during reunion in the mornings. Direct agonistic conflicts between pairs and others were rare. The acoustic analysis of loud calls revealed nine major call types. They carry signatures for sex and pair identity, and provide the substrate for signaling and the potential for recognizing pair ownership. Thus, pairs use loud call exchanges as a vocal display for signaling territory ownership, thus limiting direct aggressive encounters between neighbors and strangers. Altogether, our findings provide the first empirical evidence for the hypothesis that loud calling has evolved as a key mechanism for regulating space use and cohesiveness in dispersed pair-living primates.

Seasonality in Reproduction of Lepilemur edwardsi

Abstract: Sportive lemurs are threatened species in the IUCN Red Data Book. However, quantitative information on their reproduction, urgently required for conservation, has been lacking. We collected first data on reproductive activity of Milne-Edwards’ sportive lemurs in a population inhabiting the dry deciduous forest of the Ankarafantsika National Park in northwestern Madagascar during 1998, 2001, and 2003. The species showed a seasonal reproduction. The main mating season extended from May to June, as indicated by the presence of males with high testes volumes and estrus females. In the mating and early postmating season and in the postparturition season, sexes did not differ in body mass. Females had a significantly higher body mass than males in August and November, indicating pregnancy, which together with the presence of small infants in October and November implies that gravidity in females lasted for about 4–5 mo. All litters consisted of singletons. Individuals with body mass at the lower limit of the population either did not develop measurable testes volumes (males) or were not in estrus (females). They were probably juveniles from the previous birth season that achieved sexual maturity not before their second year after birth. The first data on reproduction suggest a low reproduction rate for Lepilemur edwardsi and a request for a higher conservation status than previously attributed and the need for further management strategies.

Complex processes of cryptic speciation in mouse lemurs from a micro-endemism hotspot in Madagascar

Abstract: Species delimitation is ever more critical for assessing biodiversity in threatened regions of the world, with cryptic species offering one of the greatest challenges. Our study focuses on a conservation hotspot in northeastern Madagascar where at least five species of mouse lemur (Microcebus spp.) occur, some of them in sympatry. One of these, M. jonahi, is described here as new to science and is accompanied by a complete genome. While morphometric analyses confirmed the cryptic nature of taxa, phylogenetic and population genetic analyses clarified species boundaries despite some interspecific gene flow, including introgression of mtDNA. The sister species pair that includes M. jonahi passed all tests of species delimitation, whereas the other pair showed more marginal results. This is at least partially due to differences in effective population sizes, which affect coalescence rates and thus influence the recently introduced genealogical divergence index (gdi). Whole-genome and RADseq analyses suggest a precipitous decline in effective population sizes associated with successive divergence events of lineages leading to the micro-endemics M. jonahi and its sister species, giving rise to grave conservation concern for both. Finally, our study demonstrates the power of genomic species delimitation approaches for revealing hidden evolutionary processes in cryptic species complexes.

Primates in Fragments

Abstract: and/or keywords. This search revealed a total of 227 papers. We randomly selected 100 of these papers and identifi ed the ways in which habitat fragmentation effects are being assessed. Evaluating and Measuring Habitat Fragmentation Habitat may be broadly defi ned as “the range of environments suitable for a given species” (Hall et al. 1997 ). For primates this generally refers to broad vegetation types, such as tropical rain forest and tropical dry forest (Arroyo-Rodríguez and Mandujano 2009 ). Because native vegetation is important for many species, numerous researchers have equated “habitat” with native vegetation (Fischer and Lindenmayer 2007 ; Arroyo-Rodríguez and Mandujano 2009 ). Habitat fragmentation is a landscape-scale process in which continuous habitat is broken apart into smaller pieces (fragments) scattered within a matrix of nonhabitat. This implies the loss of habitat and its subdivision (fragmentation) into a variable number of fragments (Fahrig 1999 ; McGarigal and Cushman 2002 ; Fahrig 2003 ). However, habitat loss can occur without the subdivision of habitat (Fig. 2.2 ), and therefore, we advocate that it will be valuable for researchers to consider analyzing the independent effects of habitat loss and fragmentation to determine whether it is the overall loss of habitat or the separation of habitat into smaller pieces (hereafter termed “habitat fragmentation per se”; sensu Fahrig 1999 , 2003 ) that actually causes negative effects on primates. This can only be done through landscape-scale studies, that is, by using landscapes as the independent units of observation (McGarigal and Cushman 2002 ; Fahrig 2003 ; Arroyo-Rodríguez and Mandujano 2009 ). By using fragments as the unit of analysis (hereafter named “fragment-scale studies”), researchers cannot differentiate between the effects of the habitat loss and the breaking apart of habitat, as both processes can result in smaller and more isolated fragments (Fahrig 2003 ; Fig. 2.2 ). Most fragmentation measures (e.g., mean fragment isolation, total amount of edge, number of fragments) are strongly related in a nonlinear manner to the amount of habitat within a landscape, in such a way that below a certain threshold of habitat area, small changes in the extent of the habitat lead to big changes in these measures (Neel et al. 2004 ). For this reason, it is often diffi cult to determine the separate effects of habitat loss and fragmentation. For instance, studies with plants (ArroyoRodríguez et al. 2009 ) and animals (Andrén 1994 ; Pardini et al. 2010 ) suggest that species diversity in a fragment of a given size may vary in landscapes with different habitat amount. Actually, the effects of fragmentation per se are thought to be relatively more important below certain thresholds of habitat amount remaining in the landscape (Andrén 1994 ; Fahrig 1997 , 1998 ; With and King 2001 ). Below this threshold of habitat amount, the probability of persistence of populations drops signifi cantly. Given the crucial management implications that these thresholds have for primate conservation, we urgently need to analyze the response of primates under different scenarios of habitat loss and fragmentation. This cannot be done through fragment-scale studies; it requires studies at the landscape scale. 2 Assessing Habitat Fragmentation Effects on Primates...

Spacing and group coordination in a nocturnal primate, the golden brown mouse lemur ( Microcebus ravelobensis ): the role of olfactory and acoustic signals

Abstract: In order to remain stable, dispersed social groups have to solve two fundamental problems: the coordination of movement and cohesiveness within a group and the spacing between the groups. Here, we investigate mechanisms involved in intra-group coordination and inter-group spacing using the golden brown mouse lemur, Microcebus ravelobensis, as a model for a nocturnal, solitary foraging mammal with a dispersed social system. By means of radiotelemetry and bioacoustics we studied the olfactory and vocal behaviour during nocturnal dispersal and reunion of five sleeping groups.

The tradeoff between torpor use and reproduction in little brown bats ( Myotis lucifugus )

Abstract: In mammals, reproduction, especially for females is energetically demanding. Therefore, during the reproductive period females could potentially adjust patterns of thermoregulation and foraging in concert to minimise the energetic constraints associated with pregnancy and lactation. We assessed the influence of pregnancy, lactation, and post-lactation on torpor use and foraging behaviour by female little brown bats, Myotis lucifugus. We measured thermoregulation by recording skin temperature and foraging by tracking bats which carried temperature-sensitive radio-tags. We found that individuals, regardless of reproductive condition, used torpor, but the patterns of torpor use varied significantly between reproductive (pregnant and lactating) females and post-lactating females. As we predicted, reproductive females entered torpor for shorter bouts than post-lactating females. Although all females used torpor frequently, pregnant females spent less time in torpor, and maintained higher skin temperatures than either lactating or post-lactating females. This result suggests that delayed offspring development which has been associated with torpor use during pregnancy, may pose a higher risk to an individual’s reproductive success than reduced milk production during lactation. Conversely, foraging behaviour of radio-tagged bats did not vary with reproductive condition, suggesting that even short, shallow bouts of torpor produce substantial energy savings, likely obviating the need to spend more time foraging. Our data clearly show that torpor use and reproduction are not mutually exclusive and that torpor use (no matter how short or shallow) is an important means of balancing the costs of reproduction for M. lucifugus.

A multidimensional approach for detecting species patterns in Malagasy vertebrates

Abstract: The biodiversity of Madagascar is extraordinarily distinctive, diverse, and endangered. It is therefore urgent that steps be taken to document, describe, interpret, and protect this exceptional biota. As a collaborative group of field and laboratory biologists, we employ a suite of methodological and analytical tools to investigate the vertebrate portion of Madagascar's fauna. Given that species are the fundamental unit of evolution, where micro- and macroevolutionary forces converge to generate biological diversity, a thorough understanding of species distribution and abundance is critical for understanding the evolutionary, ecological, and biogeographic forces that have shaped Malagasy vertebrate diversity. We illustrate the means by which we apply Mayr's "three basic tasks" of the systematist [Mayr, E. (1942) Systematics and the Origin of Species from the Viewpoint of a Zoologist (Harvard Univ. Press, Cambridge, MA)] to identify, classify, and study the organisms that together constitute Madagascar's vertebrate community. Using field inventory methods, specimen-based studies, and morphological and molecular analyses, we formulate hypotheses of species identity that then serve as the foundation for subsequent studies of biology and history. Our experience, as well as that of other investigators, has shown that much of the vertebrate species diversity in Madagascar is "cryptic" for both biological and practical reasons. Beyond issues of cryptic biological diversity, the resolution of species identity in Madagascar has been hampered because of a lack of vouchered comparative material at the population level. Through our activities, we are attempting to remedy these limitations while simultaneously enhancing research capacity in Madagascar.