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Lemurs are highly endangered mammals inhabiting the forests of Madagascar. In this study, we performed virus discovery on serum samples collected from 84 wild lemurs and identified viral sequence fragments from 4 novel viruses within the family Flaviviridae, including members of the genera Hepacivirus and Pegivirus. The sifaka hepacivirus (SifHV, two genotypes) and pegivirus (SifPgV, two genotypes) were discovered in the diademed sifaka (Propithecus diadema), while other pegiviral fragments were detected in samples from the indri (Indri indri, IndPgV) and the weasel sportive lemur (Lepilemur mustelinus, LepPgV). Although data are preliminary, each viral species appeared host species-specific and frequent infection was detected (18 of 84 individuals were positive for at least one virus). The complete coding sequence and partial 5’ and 3’ untranslated regions (UTRs) were obtained for SifHV and its genomic organization was consistent with that of other hepaciviruses, with one unique polyprotein and highly structured UTRs. Phylogenetic analyses showed the SifHV belonged to a clade that includes several viral species identified in rodents from Asia and North America, while SifPgV and IndPgV were more closely related to pegiviral species A and C, that include viruses found in humans as well as New- and Old-World monkeys. Our results support the current proposed model of virus-host co-divergence with frequent occurrence of cross-species transmission for these genera and highlight how the discovery of more members of the Flaviviridae can help clarify the ecology and evolutionary history of these viruses. Furthermore, this knowledge is important for conservation and captive management of lemurs.

The progressive fragmentation of forest habitat is causing an increase in edge areas that may differ structurally and in quality from forest interiors. We investigated the impact of edge effects on habitat structure, behaviour, and ecology of the small, nocturnal, and highly arboreal Sahamalaza sportive lemur, Lepilemur sahamalaza. To understand edge effects, we established edge-to-interior gradients using temperature, humidity, and light intensity measurements along transects. From 773 h of behavioural observations on 14 individual sportive lemurs between 2015 and 2016, we compared home range sizes, activity budgets, and habitat use of animals inhabiting the edge area and those in the core forest. We found that microclimatic edge effects penetrated the forest up to 165 m, but that there was no significant edge effect on vegetation; forest vegetation was structurally variable throughout. Individual sportive lemurs living in the edge area used more trees with a diameter at breast height of less than 5 cm but showed no other behavioural differences to individuals inhabiting the core forest. The study shows that this species may not be impacted by edge effects, at least in situations in which vegetation structure is not affected, despite microclimatic differences.

Passive acoustic monitoring, which uses autonomous audio recorders in the field, offers a powerful, efficient and cost-effective survey method that samples continuously and non-invasively. But despite its potential, its application remains atypical in primate research. We conducted a field test of passive acoustic density estimation in a near range-wide survey of the Critically Endangered Nosy Be sportive lemur ( Lepilemur tymerlachsoni ). We used the sound level of target calls detected in audio recordings as a proxy for radial distance as part of a conventional cue-counting distance sampling framework. While the passive acoustic survey recorded a large number of calls (9,560 detected calls from 250 hr of audio recordings) and the sound-level-based distance prediction model performed well, the resulting density estimates using single calls as cues were implausibly high and had low precision, which we attribute to the inherent challenges of estimating the cue rate. Results were improved, however, when using call bouts, rather than single calls, as the unit of analysis (i.e., as “cues”). Concurrent line transect surveys provided a more plausible density estimate of 303.7 individuals/km 2 (95% confidence interval = 189.6–486.3, coefficient of variation = 0.18), corresponding to a global abundance estimate of c . 11,300 individuals. Our results highlight the potential and limitations of passive acoustic density estimation and provide critical information for the conservation of one of the world’s most endangered primates.

Time is considered a resource in limited supply, and temporal niche separation is one of the most common strategies that allow ecologically similar species to live in sympatry. Mechanisms of temporal niche separation are understudied especially in cryptic animals due to logistical problems in gathering adequate data. Using high-frequency accelerometers attached to radio-collars, we investigated whether the ecologically similar lemurs Avahi meridionalis and Lepilemur fleuretae in the lowland rainforest of Tsitongambarika, south-eastern Madagascar, show temporal niche separation. Accelerometers stored data with a frequency of 1 Hz for a total of 71 days on three individuals of A. meridionalis and three individuals of L. fleuretae. We extrapolated motor activity patterns via the unsupervised learning algorithm expectation maximisation and validated the results with systematic behavioural observations. Avahi meridionalis showed peaks of activity at twilights with low but consistent activity during the day, while L. fleuretae exhibited more activity in the central hours of the night. Both lemur species had their activity pattern entrained by photoperiodic variations. The pair-living A. meridionalis was found to be lunarphilic while the solitary-living L. fleuretae was lunarphobic. We suggest that these activity differences were advantageous to minimise feeding competition, as an anti-predator strategy, and/or for dietary-related benefits. These findings demonstrate a fine-tuned temporal partitioning in sympatric, ecologically similar lemur species and support the idea that an activity spread over the 24-h, defined here as cathemerality sensu lato, is more common than previously thought in lemurs.

Temperature, rainfall, and resource availability may vary greatly within a single year in primate habitats. Many primate species show behavioral and physiological adaptations to this environmental seasonality, including changes to their diets and activity. Sahamalaza sportive lemurs (Lepilemur sahamalaza) inhabit the northwest of Madagascar and have been studied only during the dry, colder period of the year. We investigated potential effects of climate seasonality on this species by collecting behavioral data between October 2015 and August 2016, encompassing both the warmer wet and the colder dry seasons. We collected 773.15 hours of behavioral data on 14 individual sportive lemurs to investigate year-round activity budgets, ranging behavior, and sleeping site locations. Additionally we recorded temperature and rainfall data at our study site to describe the environmental conditions during the study period. The study individuals significantly decreased their time spent traveling and increased their time spent resting in the dry season compared to the wet season. Although home range size and path lengths did not differ over the study period, sleeping locations were significantly different between seasons as the lemurs focused on more confined areas in colder periods. Overall, the results indicate that Sahamalaza sportive lemur behavior varies with season, in line with reports for other primates.

Climatic changes with unpredictable weather conditions have negative effects on many primates. With several lemur species reaching their ecological limits in the dry and hypervariable spiny forest, Madagascar might provide an example for understanding adaptations of primates to unpredictable conditions. Here, we aimed to identify vegetation characteristics that allow Lepilemur petteri to persist in an environment at the limit of its ecological niche. For this, we linked the patchy distribution of the species to vegetation characteristics described on the ground and by remote sensing reflecting primary production (Enhanced Vegetation Index from MODIS) for 17 sites in nine regions, spread over 100 km along Tsimanampetsotse NP. We verified the results on a smaller scale by radio-tracking and vegetation analyses related to home ranges of 13 L. petteri. Remote sensing indicated that L. petteri is more likely to occur in forests where the variation of the annual primary production and the interannual variability of the month with the lowest primary production are low.Lepilemur petteri was more likely to occur with increasing densities of large trees, large food tree species (diameter ≥ 10 cm) and octopus trees (Alluaudia procera). Alluaudia procera provide food year-round and shelter in the spiny forest where large trees with holes are absent. High tree species diversity might buffer food availability against failure of certain tree species to produce food. These findings illustrate limiting constraints of climatic hypervariability for lemurs and indicate benefits of forest restoration with high numbers of tree species for biodiversity conservation.

The unsustainable hunting and consumption of primates destabilizes both wildlife populations and the humans who depend upon them. This is especially pertinent in Madagascar—one of the world’s poorest, least food secure, and most biodiverse countries. The people of Kirindy Mitea National Park have faced numerous famines during the prior decade. Although the park is one of Madagascar’s highest conservation priorities, researchers have yet to study the interactions between food insecurity, dietary diversity, and lemur hunting at this location. To address this gap and provide foundational data for primate conservation as well as public health policy, we surveyed forest resource exploitation, nutrition, and food security in a village adjacent to the park (N = 89 households) over 6 months (September 2018 to March 2019). We observed high levels of food insecurity and malnutrition. Of the study participants, one third had eaten a forest animal during the prior year. Of all taxa, lemurs, tenrecs, and bushpigs were hunted in the greatest numbers. Less food-secure households were more likely to hunt nonthreatened animals, such as tenrecs. Lemurs comprised one third of all wildlife consumed; households ate a mean of five (± SD 11) lemurs during the prior year. Food insecurity significantly increased within-household lemur consumption, especially the Critically Endangered red-tailed sportive lemur (Lepilemur ruficaudatus) and Vulnerable red-fronted brown lemur (Eulemur rufifrons). Our results indicate that Kirindy Mitea is among the most heavily hunted national parks in Madagascar. Given the region’s fragile environment and challenging living conditions for both its primate and human communities, the effects of hunting may be especially severe.

Speciation begins when populations become genetically separated through a substantial reduction in gene flow, and it is at this point that a genetically cohesive set of populations attain the sole property of species: the independent evolution of a population-level lineage. The comprehensive delimitation of species within biodiversity hotspots, regardless of their level of divergence, is important for understanding the factors that drive the diversification of biota and for identifying them as targets for conservation. However, delimiting recently diverged species is challenging due to insufficient time for the differential evolution of characters--including morphological differences, reproductive isolation, and gene tree monophyly--that are typically used as evidence for separately evolving lineages. In this study, we assembled multiple lines of evidence from the analysis of mtDNA and nDNA sequence data for the delimitation of a high diversity of cryptically diverged population-level mouse lemur lineages across the island of Madagascar. Our study uses a multi-faceted approach that applies phylogenetic, population genetic, and genealogical analysis for recognizing lineage diversity and presents the most thoroughly sampled species delimitation of mouse lemur ever performed. The resolution of a large number of geographically defined clades in the mtDNA gene tree provides strong initial evidence for recognizing a high diversity of population-level lineages in mouse lemurs. We find additional support for lineage recognition in the striking concordance between mtDNA clades and patterns of nuclear population structure. Lineages identified using these two sources of evidence also exhibit patterns of population divergence according to genealogical exclusivity estimates. Mouse lemur lineage diversity is reflected in both a geographically fine-scaled pattern of population divergence within established and geographically widespread taxa, as well as newly resolved patterns of micro-endemism revealed through expanded field sampling into previously poorly and well-sampled regions.

The gut microbiome is gaining recognition for its role in primate nutrition, but we stand to benefit from microbiome comparisons across diverse hosts and environmental conditions. We compared gut microbiome structure in four lemur species from four phylogenetic lineages, including 9 individual mouse lemurs (Microcebus danfossi), 6 brown lemurs (Eulemur fulvus), 20 sifakas (Propithecus coquereli), and a single sportive lemur (Lepilemur grewcockorum). In northwestern Madagascar, these species are sympatric, but use different feeding strategies to cope with environmental challenges, including relying on tree gums and insects (mouse lemurs), and some vs. significant leaf matter (brown lemurs vs. sifakas and sportive lemurs). From one fecal sample collected per lemur in the dry season in the Anjajavy Forest, we determined gut microbiome diversity, variability, and membership via 16S rRNA sequencing. The lemurs harbored strongly species-specific gut microbiomes. Brown lemurs showed more diverse and generalized consortia; mouse lemurs, sifakas, and the sportive lemur had less diverse consortia with more distinct memberships. Consistent with their fallback foods, mouse lemur microbiomes included taxa putatively associated with gum and insect digestion, whereas those of sifakas and the sportive lemur showed stronger and distinct signatures of leaf fiber and secondary compound metabolism. These results point to feeding strategy, intertwined with host phylogeny, as a driver of gut microbiome composition, but highlight real-time dietary specificity as a contributing driver of microbiome diversity. While illuminating how gut microbiomes facilitate host nutrition on challenging foods, these results help explain how ecologically diverse primates living in sympatry may differentially cope with seasonal or stochastic lean times.

Otolith shape and morphology are used to identify fish species and population stocks. The aim of this study was to distinguish the Lethrinus lentjan (Lacepede, 1802) and L. microdon (Valenciennes, 1830) (family: Lethrinidae) using otolith shape. The analyses apply the ShapeR package in R which enables to extract the outline and otolith morphology from images and for statistical examining of individual variation. Otoliths of 165 individuals from the two Lethrinus specie s were collected during 2019 and 2020. The wavelet levels were examined by using 6 wavelets to collect 63 coefficients. The regression between width and fish length were b = -0.03 (t = 2.6, P = 0.01) for L. lentjan and was significantly different (t = 2.120, P = 0.036) for L. microdon (b = 0.018).