Search

Female dominance over males is more frequent in Malagasy lemurs than in other primate clades, but patterns of female–male dominance vary among species, and few data are available for one particularly species‐rich genus, Lepilemur. We investigated the types, temporal distribution, and outcome of female–male agonistic conflicts in the Milne‐Edwards' sportive lemur (Lepilemur edwardsi). Ten L. edwardsi belonging to five social units were equipped with radio collars and observed during 79 focal follows between May and November 1998. We quantified agonistic conflicts, monthly conflict rates, and documented the winner and context for all conflicts. Female–male agonistic conflicts (N = 162) occurred at a mean rate of 0.21 conflicts/hour within groups. Agonistic conflicts peaked during the birth season and occurred mostly in unknown or infant proximity contexts. Females won 96% of all decided agonistic conflicts (N = 154). Other outcomes occurred only when females were with infants during the birth season. In that context, one female sometimes withdrew from her pair partner, and another female withdrew or fled from an extra‐group male whose attacks eventually led to infanticide. Our results suggest female dominance in pair‐living L. edwardsi. We hypothesize that elevated female aggression may convey fitness benefits to female Lepilemur because it generally allows females to intervene quickly and efficiently on behalf of their infants against nonfather males who may approach the newborn infants when they are parked in vegetation. Highlights: Intersexual conflicts occurred on a regular basis (0.21 conflicts/hour) in the nocturnal Lepilemur edwardsi.Conflicts peaked during the birth season and infant proximity was an important behavioral context for conflicts.Females won 97% (n = 134) of all decided conflicts within social units and female dominance is thus suggested for L. edwardsi. [ABSTRACT FROM AUTHOR]

Understanding landscape changes is central to predicting evolutionary trajectories and defining conservation practices. While human‐driven deforestation is intense throughout Madagascar, exceptions in areas such as the Loky‐Manambato region (north) raise questions regarding the causes and age of forest fragmentation. The Loky‐Manambato region also harbours a rich and endemic flora, whose evolutionary origin remains poorly understood. We assessed the genetic diversity of an endangered microendemic Malagasy olive species (Noronhia spinifolia Hong‐Wa) to better understand the vegetation dynamics in the Loky‐Manambato region and its influence on past evolutionary processes. We characterized 72 individuals sampled across eight forests through nuclear and mitochondrial restriction‐associated DNA sequencing data and chloroplast microsatellites. Combined population and landscape genetics analyses indicate that N. spinifolia diversity is largely explained by the current forest cover, highlighting a long‐standing habitat mosaic in the region. This sustains a major and long‐term role of riparian corridors in maintaining connectivity across these antique mosaic habitats, calling for the study of organismal interactions that promote gene flow. [ABSTRACT FROM AUTHOR]

Madagascar's flora and fauna have evolved in relative isolation since the island split from the African and Indian continents. When the last common ancestors of lemurs left Africa between 40 and 70 million years ago, they carried a subset of the viral diversity of the mainland population within them, which continued to evolve throughout the lemur radiation. Relative to other primate radiations, we know very little about the past or present viral diversity of lemurs, particularly mouse lemurs. Using high-throughput sequencing, we identified two gammaretroviruses and three betaretroviruses in the genomes of four species of wild mouse lemurs. The two gammaretroviruses and two betaretroviruses have not previously been described. One betaretrovirus was previously identified. All identified viruses are present in both Lorisiformes and Lemuriformes but absent from haplorrhine primates. The estimated ages of these viruses are consistent with the estimated divergence dates of the host lineages, suggesting they colonized the lemur genome after the Haplorrhine–Strepsirrhine split, but before the Lorisiformes–Lemuriformes split and before the colonization of Madagascar. The viral phylogenies connect multiple lineages of retroviruses from non-lemur and non-Madagascar-native species, suggesting substantial cross-species transmission occurred deep in the primate clade prior to its geographic dispersal. These phylogenies provide novel insights into known retroviral clades. They suggest that the origin of gammaretroviruses in rodents or bats may be premature and that the Jaagsiekte sheep virus clade may be older and more broadly distributed among mammals than previously thought. [ABSTRACT FROM AUTHOR]

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. KEY WORDS communication; sociality; evolution; lemur; Madagascar

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. Am J Phys Anthropol 122:251-258, 2003. KEY WORDS behavioral ecology; morphology; social system; evolution; lemur; Madagascar

Abstract Background The lemurs of Madagascar provide an excellent mammalian radiation to explore mechanisms and processes favouring species diversity and evolution. Species diversity, in particular of nocturnal species, increased considerably during the last decade. However, the factors contributing to this high diversity are not well understood. We tested predictions derived from two existing biogeographic models by exploring the genetic and morphological divergence among populations of a widely distributed lemur genus, the sportive lemur (Lepilemur ssp.) along a 560 km long transect from western to northern Madagascar. Results By using the phylogenetic analyses of mtDNA sequence data, molecular diagnostic sites and phenotypic morphometric traits, we uncovered two previously undetected species whose distributions contradict the two existing biogeographic models. Brief species descriptions are provided and a new biogeographic model is proposed (the ”large river model“). Conclusion According to the ”large river model“, large rivers in north and northwestern Madagascar acted as geographical barriers for gene flow and facilitated speciation events on a much smaller spatial scale than previously thought. Thereby, this study does not only show that species diversity in nocturnal Malagasy primates is continuously underestimated but aims to emphasize the need for conservation actions if those species with small ranges shall not face extinction in the near future.

Habituation is a preliminary process, allowing observers to become more familiar with animals and record their behavior. Few studies have described the habituation process for non-human primate species and there is a dearth of information on the habituation process among lemurs. This study describes the habituation of the Critically Endangered greater bamboo lemur (Prolemur simus). We used continuous focal animal sampling (384 hours) to collect behavioral data on seven individuals from two groups in the Vatovavy forest, southeastern Madagascar. We categorized our behavior data into two response types: habituated behaviors and non-habituated behaviors. Study animals were considered habituated when they showed an increased tolerance to human observers permitting focal animal data collection with minimal non-habituated responses. There were no significant differences among individuals for both habituated and non-habituated behaviors, therefore, all data were pooled together. Distance from observer and height of animals in the forest significantly decreased during the habituation process. By the end of the study, the frequency of habituated behaviors significantly increased. In conjunction with previously reported findings for this species, this study concludes that greater bamboo lemurs can be habituated in approximately 13-16 weeks. [ABSTRACT FROM AUTHOR]

Habitat loss and fragmentation are major ecological forces threatening animal communities across the globe. These issues are especially true in Madagascar, where forest loss is ongoing. We examined the effects of forest fragmentation on the distribution and abundance of sympatric, endemic gray, and golden‐brown mouse lemurs (Microcebus murinus and Microcebus ravelobensis), the endemic western tuft‐tailed rat (Eliurus myoxinus), and the invasive black rat (Rattus rattus) in two regions in northwestern Madagascar. We used systematic capture procedures in 40 forest fragments and four continuous forest sites which differed in size, shape, and degree of isolation. With a trapping effort of 11,567 trap nights during two dry seasons (2017–2018), we captured 929 individuals (432 M. ravelobensis, 196 M. murinus, 116 E. myoxinus, and 185 R. rattus). We examined the influence of study region, forest type (fragment vs. continuous), forest size, forest shape, the proportion of 50‐m forest edge and distance to continuous forest on the abundance and interaction of the four species. Responses to fragmentation differed strongly between species, but no interaction could be detected between the abundance of the different species. Thus competition within and between native and invasive species may not be regulating abundances in these regions. On the contrary, the abundance of M. ravelobensis and E. myoxinus differed significantly between study regions and was negatively affected by fragmentation. In contrast, there was no evidence of an impact of fragmentation on the abundance of M. murinus. Finally, the invasive R. rattus responded positively to the increasing distance to the continuous forest. In conclusion, the response of small Malagasy mammals to forest fragmentation varies largely between species, and fragmentation effects need to be examined at a species‐specific level to fully understand their ecological dynamics and complexity. Research Highlights: Habitat fragmentation affects the abundance of mouse lemurs and rodents differently.Endangered Microcebus ravelobensis and Eliurus myoxinus are more sensitive to fragmentation than Microcebus murinus and Rattus rattus.There was no evidence for interspecific competition. [ABSTRACT FROM AUTHOR]

Several bioacoustical studies are conducted to determine the geographic variations shown in the loud calls of sportive lemurs (Lepilemur sp.), which is then used for the characterization of the informative acoustic traits. The analysis has shown to be extremely useful for the development of noninvasive tools for better conservation management.

A research of a sleeping site ecology of a rain-forest dwelling sportive lemur in eastern Madagascar to determine the type, quality and use of sleeping sites and social sleeping habits of 11 focal individuals of the weasel sportive lemur (Lepilemur mustelinus), during the dry and the beginning of the rainy season is presented. The observations of the study are discussed which indicate a solitary sleeping and ranging system in the rain-forest dwelling sportive lemur with appropriate sleeping sites as invulnerable resources.

Copyright of Lemur News is the property of Lemur News 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.)

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. [ABSTRACT FROM AUTHOR]

Recent capture-recaptures of the endangered mouse lemur species (Microcebus ravelobensis), at the long-term study site Jardin Botanique B in the Ankarafantsika National Park (about 1km away from the park headquarters in Ampijoroa), point to a decline in population size. In order to assess long-term fluctuations of mouse lemur abundance in more depth and to determine the potential beginning of the decline, capture data of the golden brown mouse lemur were analysed over a period of 20 years from 1996 - 2016. Monthly population sizes were estimated by the Jolly-Seber method, and absolute capture results per trapping night were taken as another proxy of abundance. Both the nightly capture frequencies and the calculated population sizes, show monthly and yearly variations but suggest a relatively constant number of animals until 2010 with high capture success (>40 animals/night) in August/September 2010, and a decreasing capture success down to less than ten animals/ night in September 2016. The same applies to the calculated population size that declined from 52 in September 2010 to 13 in September 2016. No obvious relationship could be identified between the population size and rainfall or temperature dynamics, although a temporal effect of a severe cyclone in 2011 cannot be excluded. Intensified human use of the forest, e.g. for wood exploitation or hunting during times of political instability, or reduced monitoring activities are further likely explanatory variables. This potential decline of an endangered Malagasy mouse lemur calls for immediate attention, and we suggest the implementation of a long-term monthly population monitoring program in addition to protective measures such as routine patrolling activities. These should, if necessary, lead to law enforcement actions in the area to prevent further illegal human activities in the forest. [ABSTRACT FROM AUTHOR]

Animal vocalizations are an interesting non-invasive bioacoustic tool for the monitoring of cryptic and endangered lemur species such as Otto's sportive lemur (Lepilemur otto). To date, information on the biology, ecology, and bioacoustics of this newly described species is lacking. We provide first data on its population density and vocal acoustics in the Inter-river-system II, the Bongolava forest, Sofia region, northwestern Madagascar. Data collection was carried out in three different sites (Marosely, Antsahonjo and Ankarahara) with typical dry deciduous forest. Seven acoustically distinct call types could be recorded. This preliminary vocal repertoire of L. otto was similar to the vocal repertoire of L. edwardsi, its sister species occurring in the Inter-River-System I. However, there were also tangible differences in some acoustic parameters between the two species. Abundance data imply that this lemur species is highly threatened due to bush fires and the high fragmentation of its habitat. Findings provide the first basis to establish bioacoustic tools for non-invasive assessment of the presence, distribution and monitoring of this species. A more comprehensive study, integrating vocal acoustic data with abundance and chronic stress hormone and population genetic data, is urgently needed to establish management plans for the future protection of this highly endangered sportive lemur species. [ABSTRACT FROM AUTHOR]