Golden-brown mouse lemur

About: Golden-brown mouse lemur is a research topic. Over the lifetime, 13 publications have been published within this topic receiving 646 citations. The topic is also known as: Microcebus ravelobensis.

Seasonal Changes in Feeding Ecology and Activity Patterns of Two Sympatric Mouse Lemur Species, the Gray Mouse Lemur (Microcebus murinus) and the Golden-brown Mouse Lemur (M. ravelobensis), in Northwestern Madagascar

Abstract: Because closely related species are likely to be ecologically similar owing to common ancestry, they should show some degree of differentiation in order to coexist. We studied 2 morphologically similar congeneric species, the golden-brown mouse lemur (Microcebus ravelobensis) and the gray mouse lemur (M. murinus). These species are found in partial sympatry in the dry deciduous forest in northwestern Madagascar. We investigated whether 1) feeding niche differentiation and/or 2) a reduction in locomotor activity during periods of food shortage, which might reflect an energy saving strategy, can explain the coexistence of these 2 lemur species. To obtain feeding and behavioral data, we conducted focal observations of 11 female Microcebus murinus and 9 female M. ravelobensis during 11 months from 2007 to 2008 and collected fecal samples for 6 mo. We monitored the phenology of 272 plant specimens and trapped arthropods to determine food availability. Results revealed interspecific differences in 1) relative proportion of consumed food resources, resulting in a merely partial dietary overlap, and in 2) relative importance of seasonally varying food resources throughout the year. In addition, females of Microcebus murinus showed a reduction in locomotor activity during the early dry season, which might reflect an energy-saving strategy and might further reduce potential competition with M. ravelobensis over limited food resources. To conclude, a combination of interspecific feeding niche differentiation and differences in locomotor activity appears to facilitate the coexistence of Microcebus murinus and M. ravelobensis.

Natural and anthropogenic determinants of genetic structure in the largest remaining population of the endangered golden-brown mouse lemur, Microcebus ravelobensis.

Abstract: Genetic differentiation between natural populations is best understood as a result of both natural and anthropogenic factors. Genetic studies on large populations still living under relatively undisturbed conditions are extremely valuable to disentangle these influences. The effect of three natural (geographic distance, landscape, dispersal) factors and two anthropogenic factors (road, savannah) on gene flow was analyzed in the largest remaining forest region in the range of the endangered golden-brown mouse lemur in Madagascar. A total of 187 individuals from 12 sites were sampled and genotyped at eight polymorphic microsatellite loci. All sites exhibited similar levels of genetic variation. The level of genetic differentiation was low to moderate with pairwise F(ST) values ranging from -0.002 to 0.12, but most were significant and all sites exhibited high self-assignment rates. A spatial autocorrelation analysis was performed at two geographic scales revealing a pattern of isolation-by-distance and suggesting that no clear differences exist between male and female local dispersal. Two Bayesian approaches revealed that a stretch of savannah represented a significant barrier to movement, whereas the influence of the road on gene flow was less clear. Finally, we found that landscape characteristics, in particular altitude, play a role in the functional connectivity of the sites. The study underlines the importance of studies in relatively undisturbed conditions for the interpretation of population genetics data in fragmented environments. The results are discussed in terms of their conservation relevance for forest-dwelling animals such as most primate species.

MtDNA reveals strong genetic differentiation among geographically isolated populations of the golden brown mouse lemur, Microcebus ravelobensis

Abstract: Microcebus ravelobensis is an endangered nocturnal primate endemic to northwestern Madagascar. This part of the island is subject to extensive human intervention leading to massive habitat destruction and fragmentation. We investigated the degree of genetic differentiation among remaining populations using mitochondrial control region sequences (479–482 bases). Nine populations were sampled from the hypothesized geographic range. The region is composed of three inter-river systems (IRSs). Samples were collected in three areas of continuous forests (CFs) and six isolated forest fragments (IFFs) of different sizes. We identified 27 haplotypes in 114 animals, with CFs and IFFs harbouring 5–6 and 1–3 haplotypes, respectively. All IFFs were significantly differentiated from each other with high ΦST values and sets of unique haplotypes. The rivers constitute significant dispersal barriers with over 82% of the molecular variation being attributed to the divergence among the IRSs. The data suggest a deep and so far unknown split within the rufous mouse lemurs of northwestern Madagascar. The limited data base and the lack of ecological and morphological data do not allow definite taxonomic classification at this stage. However, the results clearly indicate that M.ravelobensis consists of three evolutionary significant units, possibly cryptic species, which warrant urgent and separate conservation efforts.

Sociogenetic structures, dispersal and the risk of inbreeding in a small nocturnal lemur, the golden-brown mouse lemur (Microcebus ravelobensis)

Abstract: Summary Natal dispersal reduces the risk of inbreeding, since it is typically biased towards one sex. Golden-brown mouse lemurs {Microcebus ravelobensis) form mixed-sex sleeping groups whose genetic composition is not yet known. This study investigates the composition of eight sleeping groups and the dispersal pattern in a free-living population of this nocturnal primate. Genetic relatedness and parentage was calculated for 101 individuals (43 males, 58 females) based on microsatellite analyses. Matrilinear relatedness played a major role in the composition of sleeping groups. Co-sleepers were significantly more closely related than members of different sleeping groups. Dispersal was not strongly biased towards one sex. More than 50% of all potential sons (N = 19) and daughters (N = 26) remained in their natal range well into their first mating season, but potential sons disappeared more frequently than daughters lateron. These data indicate that many sons may have delayed their dispersal. This delayed dispersal may have increased the risk of inbreeding, since closely related males and females stayed within one home range diameter of each other quite regularly in the mating season. In fact, two definite cases of inbreeding were detected. The likely benefits of delayed dispersal are discussed in view of the confirmed cases of inbreeding.

Leaf nest use and construction in the golden‐brown mouse lemur (Microcebus ravelobensis) in the Ankarafantsika National Park

Abstract: The use of leaf nests has been documented in several mouse lemur species over the last few decades, including the golden-brown mouse lemur. Nest construction, however, has only rarely been observed and detailed descriptions of this process are lacking so far. We aim to determine the relative importance of leaf nests as shelters for the golden-brown mouse lemur, and to test predictions concerning the role of thermoregulation, safety (i.e., protection of infants), and of interspecific competition with the sympatric gray mouse lemurs in regulating nest use. Finally, we intend to clarify whether and how Microcebus ravelobensis constructs the nests, and we provide physical descriptions of seven leaf nests. Nocturnal focal observations were carried out from May 2007 to January 2008 on 18 females, and sleeping sites were regularly monitored during a six-month period. Data were collected from two study sites, one with exclusive presence of M. ravelobensis, and one with co-existence of the two mouse lemur species. Sixty-five out of 379 identified daily sleeping sites were leaf nests. These represented a total of 35 different leaf nests, used by 15 out of 18 females. The relative leaf nest use differed between sites during five out of six months, but without a consistent pattern. Interspecific competition can therefore not explain leaf nest use. Leaf nest use differed seasonally and may be partly explained by thermoregulatory advantages in the site with lower minimum temperatures. Nest use was furthermore higher than expected in both sites during the rearing season that indicates the role of nests in infant protection. For the first time, we could confirm that golden-brown mouse lemurs build leaf nests themselves. Nest building lasted between 46 and 68 min, which shows that this task is time consuming and therefore probably costly. Am. J. Primatol. 72:48–55, 2010. © 2009 Wiley-Liss, Inc.