Trachypithecus Leucocephalus Research Articles

Genomic adaptation to small population size and saltwater consumption in the critically endangered Cat Ba langur

Many mammal species have declining populations, but the consequences of small population size on the genomic makeup of species remain largely unknown. We investigated the evolutionary history, genetic load and adaptive potential of the Cat Ba langur (Trachypithecus poliocephalus), a primate species endemic to Vietnam’s famous Ha Long Bay and with less than 100 living individuals one of the most threatened primates in the world. Using high-coverage whole genome data of four wild individuals, we revealed the Cat Ba langur as sister species to its conspecifics of the northern limestone langur clade and found no evidence for extensive secondary gene flow after their initial separation. Compared to other primates and mammals, the Cat Ba langur showed low levels of genetic diversity, long runs of homozygosity, high levels of inbreeding and an excess of deleterious mutations in homozygous state. On the other hand, genetic diversity has been maintained in protein-coding genes and on the gene-rich human chromosome 19 ortholog, suggesting that the Cat Ba langur retained most of its adaptive potential. The Cat Ba langur also exhibits several unique non-synonymous variants that are related to calcium and sodium metabolism, which may have improved adaptation to high calcium intake and saltwater consumption.

Diets of white-headed langurs (Trachypithecus leucocephalus) inhabiting limestone forests: The effects of habitat fragmentation and implication for conservation.

Information about wildlife diets is crucial for comprehending how species adapt to varying environments in fragmented habitats and for developing effective conservation strategies. White-headed langurs (Trachypithecus leucocephalus) are exclusively found in fragmented limestone forests in southwestern China. To investigate the effects of habitat fragmentation on langurs' diets, we collected published dietary data and relevant environmental factors spanning from 1996 to 2021 at two regions with different degrees of fragmentation (Banli > Bapen), from 10 studies (three of Banli and seven of Bapen). The results demonstrated that the diets of white-headed langurs were significantly influenced by environmental factors, including habitat fragmentation, annual rainfall, and mean annual temperature. Food item diversity index was significantly and positively affected by the fragmentation index, the higher fragmentation the langurs suffered, the more diverse food items they consumed. Besides, fruit consumption was negatively influenced by annual rainfall and the consumption of other items was influenced by mean annual temperature. Notably, although there are no significant differences in the feeding proportions of food items or food item diversity indices were observed between the Banli and Bapen groups, the Banli groups extensively consumed ground-supported kudzu (Pueraria montana var. lobata), a plant rarely recorded in the dietary preferences of the Bapen groups, implying that the large plants likely lacking in the fragmented limestone forests. Our findings provide evidence of the major impact of habitat fragmentation on the dietary composition of white-headed langurs, highlighting the need of considering the possibility that the habitats of the white-headed langurs have all undergone extreme fragmentation, inferring the conservation efforts should prioritize protecting native vegetation and reducing human disturbance.

Antibiotic resistance profiles of gut microbiota across various primate species in Guangxi.

Understanding the gut microbiota and antibiotic resistance gene (ARG) profiles in non-human primates (NHPs) is crucial for evaluating their potential impact on human health and the environment. In this study, we performed metagenomic analysis of 203 primate fecal samples, including nine NHP species and humans, to comprehensively characterize their gut microbiota and ARGs. Our study reveals the prevailing phyla in primates as Firmicutes, Bacteroidetes, Euryarchaeota, and Proteobacteria. The captive NHPs exhibited higher ARG abundance compared to their wild counterparts, with tetracycline and beta-lactam resistance genes prevailing. Notably, ARG subtypes in Trachypithecus leucocephalus (T. leucocephalus) residing in karst limestone habitats displayed a more dispersed distribution compared to other species. Interestingly, ARG profiles of NHPs clustered based on geographic location and captivity status. Co-occurrence network analysis revealed intricate correlations between ARG subtypes and bacterial taxa. Procrustes analysis unveiled a significant correlation between ARGs and microbial phylogenetic community structure. Taxonomic composition analysis further highlighted differences in microbial abundance among NHPs and humans. Our study underscores the impact of lifestyle and geographical location on NHP gut microbiota and ARGs, providing essential insights into the potential risks posed by NHPs to antibiotic resistance dissemination. This comprehensive analysis enhances our understanding of the interplay between NHPs and the gut resistome, offering a critical reference for future research on antibiotic resistance and host-microbe interactions.

Nighttime behaviors of white-headed langurs (Trachypithecus leucocephalus): The role of predation avoidance and thermoregulation

We collected nighttime behavioral data by observing a group of white-headed langurs (Trachypithecus leucocephalus), comprising 16 individuals in a limestone forest in Guangxi Chongzuo National Nature Reserve, China, from October 2016 to August 2017. We recorded various aspects of the langurs’ nighttime behavior, including the duration of entering/leaving sleeping sites, the duration of remaining in sleeping sites, the duration and frequency of movement, and the number and size of sleeping clusters in sleeping sites. The primary aim was to investigate thermoregulation strategy in these primates at night. By applying thermoregulation hypotheses, we aimed to elucidate the underlying factors driving seasonal changes in white-headed langurs’ nighttime behavior. All individuals took 7.53 ± 1.16 min entering sleeping sites, and took 9.70 ± 3.05 min leaving sleeping sites, which could be a response to predation risk. Movement throughout the night was observed in most individuals. Sleeping clusters were formed by white-headed langurs during the night, with larger clusters sizes occurring in the cold season (4.68 ± 0.69) compared with the hot season (3.59 ± 0.77). additionally, langurs prolonged their stay in sleeping sites during the cold season (12.36 ± 0.63 h) compared with the hot season (11.20 ± 0.63 h), potentially as a thermoregulation strategy to combat low temperature. Our findings indicate that temperature, rainfall, day length and food availability influence the nighttime behavior of white-headed langurs, highlighting the importance of ecological variables in determining primate nocturnal behavioral responses. The observed changes in white-headed langurs’ nighttime behavior strongly support their inclination toward behavioral strategies that minimize thermoregulation costs in limestone forests.

Population dynamics and conservation status of the white-headed langur in the Chongzuo forest fragments, Guangxi, China

AbstractWe present the results of two population surveys conducted 10 years apart (December 2010–February 2011 and December 2020–January 2021) of the Critically Endangered white-headed langur Trachypithecus leucocephalus in the Chongzuo White-Headed Langur National Nature Reserve, Guangxi Province, China. In the first survey, we recorded 818 individuals in 105 groups and 16 solitary adult males. In the second survey, we recorded 1,183 individuals in 128 groups and one solitary adult male. As a result of government policies, poaching for food and traditional medicine is no longer a primary threat to these langurs. However, severe forest loss and fragmentation caused by human activities could limit any future increase of this langur population.

Seasonal variations in the gut microbiota of white-headed black langur (Trachypithecus leucocephalus) in a limestone forest in Southwest Guangxi, China

Investigating gut microbiota is important for understanding the physiological adaptation of animals to food availability changes in fragmented habitats and consequently providing new ideas for the conservation of endangered wild animals. In this study, we explored the gut microbiota of the endangered white-headed black langur (Trachypithecus leucocephalus), which is endemic to the limestone forests of Southwest Guangxi, China, to understand its adaptation strategies to seasonal changes in habitat using 16S rRNA sequencing. Our results revealed significant seasonal variations in the gut microbiota of white-headed black langurs. In particular, the alpha diversity was higher in the rainy season than in the dry season, and the beta diversity was significantly different between the two seasons. At the phylum level, the relative abundance of Firmicutes, Actinobacteriota, and Proteobacteria was higher in the dry season than that in the rainy season, whereas that of Bacteroidetes, Spirochaetota, and Cyanobacteria was significantly higher in the rainy season than that in the dry season. At the family level, Oscillospiraceae and Eggerthellaceae were more abundant in the dry season than in the rainy season, whereas Lachnospiraceae, Ruminococcaceae, and Monoglobaceae were more abundant in the rainy season than in the dry season. These results could have been obtained due to seasonal changes in the diet of langurs in response to food plant phenology. In addition, the neutral community model revealed that the gut microbiota assembly of these langurs was dominated by deterministic processes and was more significantly affected by ecological factors in the dry season than in the rainy season, which could be linked to the higher dependence of these langurs on mature leaves in the dry season. We concluded that the seasonal variations in the gut microbiota of white-headed black langurs occurred in response to food plant phenology in their habitat, highlighting the importance of microbiota in responding to fluctuating ecological factors and adapting to seasonal dietary changes.

Gut microbiota of white-headed black langurs (Trachypithecus leucocephalus) in responses to habitat fragmentation.

The white-headed black langur (Trachypithecus leucocephalus) is exclusively distributed in the karst forests and is critically endangered owing to habitat fragmentation. Gut microbiota can provide physiological data for a comprehensive study of the langur's response to human disturbance in the limestone forest; to date, data on spatial variations in the langurs' gut microbiota are limited. In this study, we examined intersite variations in the gut microbiota of white-headed black langurs in the Guangxi Chongzuo White-headed Langur National Nature Reserve, China. Our results showed that langurs in the Bapen area with a better habitat had higher gut microbiota diversity. In the Bapen group, the Bacteroidetes (13.65% ± 9.73% vs. 4.75% ± 4.70%) and its representative family, Prevotellaceae, were significantly enriched. In the Banli group, higher relative abundance of Firmicutes (86.30% ± 8.60% vs. 78.85% ± 10.35%) than the Bapen group was observed. Oscillospiraceae (16.93% ± 5.39% vs. 16.13% ± 3.16%), Christensenellaceae (15.80% ± 4.59% vs. 11.61% ± 3.60%), and norank_o__Clostridia_UCG-014 (17.43% ± 6.64% vs. 9.78% ± 3.83%) were increased in comparison with the Bapen group. These intersite variations in microbiota diversity and composition could be accounted for by differences in food resources caused by fragmentation. Furthermore, compared with the Banli group, the community assembly of gut microbiota in the Bapen group was influenced by more deterministic factors and had a higher migration rate, but the difference between the two groups was not significant. This might be attributed to the serious fragmentation of the habitats for both groups. Our findings highlight the importance of gut microbiota response for the integrity of wildlife habitats and the need in using physiological indicators to study the mechanisms by which wildlife responds to human disturbances or ecological variations.

Preference and Seasonality of Allogrooming Posture and Body Site of Wild White-Headed Black Langurs (Trachypithecus leucocephalus) in Guangxi, China: Functional Implications

Preference and Seasonality of Allogrooming Posture and Body Site of Wild White-Headed Black Langurs (Trachypithecus leucocephalus) in Guangxi, China: Functional Implications

Climate change and human activities promoted speciation of two endangered langurs (François' langur and white-headed langur)

Climate oscillations may drive the divergence of ancestral species through climatic suitability isolation, effective population contraction, and the cessation of gene flow. However, traditional ecological niche models fail to consider gene flow and the historical demography of a species, and thus provide limited insight into how climate oscillations affect species divergence. We analyzed the impact of climate change and human activities on the divergence of two langur species, François' langur (Trachypithecus francoisi) and white-headed langur (T. leucocephalus) using Maxent models and genomic data. Our results indicate that 1) although gene flow occurred between François’ langurs and white-headed langurs during the Last Interglacial (LIG, 140–120 Kya), the two species showed disparate climatic suitability; 2) both taxa were characterized by a decrease in effective population size and a cessation of gene flow during the Last Glacial Maximum (LGM, 26.5–19 Kya), which promoted speciation of the two langurs; and 3) The effective population size and areas of climatic suitability for both species increased from the LGM to the present. More recently, human activities severed the geographical link between the two species, leaving no opportunity for gene flow. Climate oscillation, population isolation, and in situ evolution in refugia appear to have played a critical role in limiting gene flow between these two langur species, however human activities have contributed to species differentiation. Overall, our results demonstrate how climatic oscillations and human activities drive speciation, providing a new perspective on species divergence and conservation.

Pattern of play behavior in infant (age 1 to 12 months) white-headed langurs in limestone forests, southwest China.

Play behavior is a significant trait of immature nonhuman primates (hereafter primates) that plays an important role in sensory, locomotor, socio‐cognitive, and developmental processes. It has been suggested that the function of play is to practice and improve motor skills related to foraging, avoiding predators, attracting mates, raising offspring, and strengthening the skills needed for the formation and maintenance of social bonds. From September 2009 to August 2010, we investigated the play behavior of 1–12 month‐old infant white‐headed langurs (Trachypithecus leucocephalus) a Critically Endangered primate species endemic to China. We carried out this study in the Guangxi Chongzuo White‐headed Langur National Nature Reserve, and recorded 4421 play bouts and 1302 min of play engaged in by seven infants. We found that infants of different ages exhibited different patterns of play behavior. Specifically, nonsocial play behaviors appeared at one month of age, social play behaviors at two months, and an expanded repertoire of social and non‐social play behaviors at three months of age. The frequency and duration of nonsocial play peaked at five months of age and then decreased, while social play gradually increased with age. Nonsocial play did not differ between the sexes, whereas social play showed sex specificity, with a higher frequency and longer duration of social play in male infants compared to female infants. In addition, male and female white‐headed langur infants appeared to prefer individuals of same sex as social playmates, but no obvious choice preference for a specific individual. In conclusion, we provide the first report of play behavior in a population of wild Critically Endangered white‐headed langurs. We suggest that age‐ and sex‐specific differences in play behavior of infants form the bases for age and sex‐based differences in the social interactions of adult langurs.

Habitat use of the white-headed langurs in limestone forest of Southwest Guangxi, China: Seasonality and group size effects.

Understanding how animals cope with habitat‐specific environmental factors can assist in species conservation management. We studied the habitat use of four groups (two large and two small groups) of white‐headed langurs (Trachypithecus leucocephalus) living in the forest of southwest Guangxi, China between September 2016 and February 2017 via instantaneous scan sampling. Our results showed that the langurs primarily used hillsides (55.91% ± 6.47%), followed by cliffs (29.70% ± 5.48%), hilltops (7.26% ± 3.55%), flat zones (6.99% ± 6.58%), and farmlands (0.14% ± 0.28%). The langurs moved most frequently on hillsides (49.35% ± 6.97%) and cliffs (35.60% ± 9.17%). The hillsides were more frequently used (66.94% ± 7.86%) during feeding, and the langurs increased the use of hilltops during the rainy season, and the use of cliffs in the dry season. The langurs frequently rested on hillsides (49.75% ± 8.16%) and cliffs (38.93% ± 8.02%). The larger langur group used cliffs more frequently when moving and resting, whereas the small langur group used hillsides more frequently while resting. Langurs in all groups avoided the flat zones for feeding. Their use of habitat reflected the balancing of foraging needs, thermoregulation, and predator avoidance. We conclude that the ecological factors are determinants of habitat use for white‐headed langurs. Our findings suggest that conservation efforts should focus on protecting the vegetation on the hillsides and restoring the vegetation on the flat zones.

Comparative Gut Microbiome in Trachypithecus leucocephalus and Other Primates in Guangxi, China, Based on Metagenome Sequencing.

The Trachypithecus leucocephalus (white-headed langur) is a highly endangered, karst-endemic primate species, inhabiting the karst limestone forest in Guangxi, Southwest China. How white-headed langurs adapted to karst limestone and special dietary remains unclear. It is the first time to study the correlation between the gut microbiome of primates and special dietary, and environment in Guangxi. In the study, 150 fecal samples are collected from nine primates in Guangxi, China. Metagenomic sequencing is used to analyze and compare the gut microbiome composition and diversity between white-headed langurs and other primates. Our results indicate that white-headed langurs has a higher diversity of microbiome than other primates, and the key microbiome are phylum Firmicutes, class Clostridia, family Lachnospiraceae, and genera Clostridiates and Ruminococcus, which are related to the digestion and degradation of cellulose. Ten genera are significantly more abundant in white-headed langurs and François’ langur than in other primates, most of which are high-temperature microbiome. Functional analysis reveals that energy synthesis-related pathways and sugar metabolism-related pathways are less abundant in white-headed langurs and François’ langur than in other primates. This phenomenon could be an adaptation mechanism of leaf-eating primates to low-energy diet. The gut microbiome of white-headed langurs is related to diet and karst limestone environment. This study could serve as a reference to design conservation breeding, manage conservation units, and determine conservation priorities.

Food availability, temperature, and day length drive seasonal variations in the positional behavior of white-headed langurs in the limestone forests of Southwest Guangxi, China.

Information on positional behavior contributes to the understanding of the ecological adaptation mechanisms in animals. We collected data on the positional behavior of white‐headed langurs (Trachypithecus leucocephalus) at the Guangxi Chongzuo White‐Headed Langur National Nature Reserve from September 2016 to August 2017 via instantaneous scan sampling method. This study aimed to examine the importance of positional behavior flexibility in limestone forests characterized by seasonal variations in climate and food resources. Our results indicated that langurs adopted leaping (47.92% ± 5.50%) and vertical climbing (40.13% ± 6.20%) as their predominant locomotor modes and sitting (83.08% ± 4.70%) as their predominant posture. Their positional behavior exhibited marked seasonal variations. More specifically, langurs used quadrupedal walking more frequently during the dry season than during the rainy months. In the stationary state, they sat more frequently during the dry season, whereas they laid and suspended more often during the rainy season. Their positional behavior was affected by fruit availability, day length, and temperature. Quadrupedal walking increased with the decrease in fruit availability, whereas leaping was positively correlated with fruit availability. Moreover, sitting was positively correlated with average temperature but negatively correlated with day length. Lying was also negatively correlated with temperature but positively correlated with day length. We conclude that white‐headed langurs adapt to limestone forests with positional behavior flexibility in response to seasonality. Our research provides evidence of the effects of food availability, ambient temperature, and day length on the positional behavior of white‐headed langurs, highlighting the need to understand their behavioral ecology and the influence of ecological factors on behavioral adaptation.

Interannual variation in food choice of white-headed langur inhabiting limestone forests in Fusui, southwest Guangxi, China.

Food habits are important factors in the adaptation of wild nonhuman primates. White‐headed langurs (Trachypithecus leucocephalus) are endemic to heavily fragmented limestone forests and adapt to unique living environments via flexible food selection strategies. In this study, we compared the dietary data for white‐headed langurs living in Chongzuo White‐headed Langur National Nature Reserve in 2013 and 2016 to evaluate interannual variations in diet. Our results indicated that young leaves were the main food source for langurs, accounting for 52.4% (SD 25.4%) and 65.2% (SD 22.4%) of their diet in 2013 and 2016, respectively. The pattern of plant part consumption was similar between the two years. The consumption of young leaves varied with the availability of young leaves, whereas the consumption of mature leaves was negatively correlated with young leaf availability. The consumption of plant species and diet diversity were higher in 2013 than in 2016. In both 2013 and 2016, although diet diversity varied with the consumption of mature leaves, it was negatively correlated with the consumption and availability of young leaves. Dietary interannual variation is likely to either be linked to phenological variations or indicate that white‐headed langurs have a flexible ecological adaptation coping with habitat fragmentation.

Investigation and Evaluation of Plant Resources Based on Modern Digital Rural Eecotourism Development

The establishment of natural ecological reserves has effectively protected the original ecological environment and natural resources to a certain extent. Bima Mountain Nature Reserve is rich in animal and plant resources. The main plants in the reserve are naturally growing subtropical evergreen broad-leaved forest. There are 36 species of national key protected plants in the reserve, such as silver fir and dove tree. The clouded leopard, black langur and white-headed langur are the first class protected animals in the state. According to the results of the survey and evaluation, combined with the local ecotourism foundation put forward the following Suggestions: the best characteristics of ornamental plants in country garden, characteristic feature edible plants in the country kitchen, healthy development of green economy, open up knowledge, white horse hill features of plant industry, increase the reserve fomous trees protect plants, the protection of both inside and outside. This study through field investigation, the early use of analytic hierarchy and private access methods, such as the white horse hill ecological nature reserve resources comprehensive evaluation on the plants, and in a lot of Zhu Wu kinds of screening and recommend a more suitable for local ecological tourism development characteristics of ornamental plants, edible plants, medicinal plants, as well as the key protection plant, to the local developing ecological tourism provides an important reference basis, also for the reasonable solution to reserve conflicts between people and provides a reference model.

The reference genome and transcriptome of the limestone langur, Trachypithecus leucocephalus, reveal expansion of genes related to alkali tolerance

BackgroundTrachypithecus leucocephalus, the white-headed langur, is a critically endangered primate that is endemic to the karst mountains in the southern Guangxi province of China. Studying the genomic and transcriptomic mechanisms underlying its local adaptation could help explain its persistence within a highly specialized ecological niche.ResultsIn this study, we used PacBio sequencing and optical assembly and Hi-C analysis to create a high-quality de novo assembly of the T. leucocephalus genome. Annotation and functional enrichment revealed many genes involved in metabolism, transport, and homeostasis, and almost all of the positively selected genes were related to mineral ion binding. The transcriptomes of 12 tissues from three T. leucocephalus individuals showed that the great majority of genes involved in mineral absorption and calcium signaling were expressed, and their gene families were significantly expanded. For example, FTH1 primarily functions in iron storage and had 20 expanded copies.ConclusionsThese results increase our understanding of the evolution of alkali tolerance and other traits necessary for the persistence of T. leucocephalus within an ecologically unique limestone karst environment.

基于野外观测检验动物廊道选址模型的准确性——以白头叶猴为例

廊道构建是减少栖息地破碎化负面影响的重要策略之一。目前，已经有许多模型用于动物廊道的选址，而"选址模型是否能准确预测动物迁移的实际发生位置"一直是保护生物学最为关注的问题。最小成本路径模型（LCP）和条件最小成本廊道模型（CMTC）是两种较为常用的廊道选址模型。以白头叶猴（Trachypithecus leucocephalus）为目标物种，分别运用LCP和CMTC模拟生成白头叶猴迁移廊道，将模拟结果与野外观测廊道进行对比，检验两种方法的准确性。结果表明：与野外观测实际廊道相比，LCP模型模拟结果的完全准确率为46.7%，部分准确率为20%，完全不准确率为33.3%；CMTC模型模拟结果的完全准确率为26.7%，其余73.3%为部分准确，无完全不准确的结果；总体上看，CMTC廊道的准确率较LCP高，因而CMTC模型模拟白头叶猴实际迁移廊道位置的准确性优于LCP模型。输入"源"要素类型、阻力面栅格尺度设定、栖息地土地利用类型变化以及动物迁移行为复杂性4个因素是影响该模拟结果准确性的主要原因。;Habitat fragmentation is a hot issue of global biodiversity conservation, and corridor construction is one of the important strategies to reduce the negative impact of habitat fragmentation. To date, many models have been used for the prediction location of animal corridors, one key concern from conservation biologist is whether these models can accurately predict actual dispersal paths of target species. In this work, the white-headed langur (Trachypithecus leucocephalus), an unique endangered primate to Guangxi, China, was chosen as target species, it inhabits karstic rocky mountain areas, where is facing severe fragmentation problems due to increased human disturbance. During the last century, this species experienced a severe population declines, with an estimated 80% contraction in its distribution and a 60% reduction in its total population. They are now only distributed in small isolated habitat patches with limited opportunities to exchange gene among populations. The corridors can help this species disperse from one patch to another, and the connectivity of isolated patches is enhanced consequently. Least Cost Path (LCP) model and Conditional Minimum Transit Cost (CMTC) model are two commonly used corridor site selection models, whereas their outputs have never been validated using the actual observations data. For this purpose, LCP model and CMTC model were used to simulate the dispersal corridors of T. leucocephalus, respectively, and the simulation results from two models were further compared with field observated data for the accuracy test of these two models. The results revealed that:The fully accuracy rate for predictions of LCP model was 46.7%, partial accuracy was 20%, the complete inaccuracy rate was 33.3%. The full accuracy rate for predictions of CMTC model was 26.7%, the remnant 73.3% were all partially accurate and there was no completely inaccurate outputs from CMTC model. In general, the accuracy rate for predictions of CMTC model was higher than the outcome of LCP model, and thus the CMTC model had better performance on prediction for corridor location of T. leucocephalus than LCP model. The type of input source feature, grid size configuration of cost surface, changes in habitat land use types and complexity of animal movement behavior were four main factors affecting the accuracy of model prediction results.

广西扶绥白头叶猴对栖息地的选择与利用

为了解白头叶猴（Trachypithecus leucocephalus）的栖息地利用规律及其影响因素，2016年2月至2017年1月，采用瞬时扫描取样法对广西崇左白头叶猴国家级自然保护区一群白头叶猴的栖息地利用进行了研究。结果表明，白头叶猴对山体不同部位的利用存在显著性差异（χ² =39.467，df=3，P<0.001），其中，对崖壁（56.75±9.55）%的利用比例最大，其次是对山坡（39.42±10.93）%和山顶（2.98±2.54）%的利用，而对山脚（0.84±1.47）%的利用频率最低。白头叶猴对不同微生境类型的利用存在差异（χ²=27.709，df=3，P<0.001），其中对乔木（49.37±12.31）%的利用比例最大，其次是裸岩（24.05±13.61）%，随后依次为藤本（15.48±8.01）%和灌木（10.87±5.45）%。白头叶猴主要在山坡上觅食，利用崖壁移动、休息，进行社会活动；主要利用裸岩进行社会活动，觅食、移动、休息主要发生在乔木上。从整体来看，白头叶猴在雨季对乔木的利用频率显著大于旱季（Z=-2.680，n=12，P=0.007）；雨季在山坡觅食频率显著大于旱季（Z=-2.517，n=12，P=0.012），而在崖壁觅食频率刚好相反（Z=-2.842，n=12，P=0.004）；白头叶猴雨季在乔木休息的频率显著大于旱季（Z=-2.355，n=12，P=0.019）。白头叶猴对栖息地的利用受到温度的影响。白头叶猴对乔木的总体利用频率随着平均温度的升高而增加（r=0.664，n=12，P=0.018）；觅食时，对崖壁、裸岩的利用频率均与平均温度成负相关关系（崖壁：r=-0.685，n=12，P=0.014；裸岩：r=-0.600，n=12，P=0.039）；休息时，对乔木的利用频率与平均温度呈正相关关系（r=0.650，n=12，P=0.022）。不同季节，白头叶猴对栖息地的利用方式不同。白头叶猴的栖息地利用模式可能是在觅食利益和捕食风险之间作出的权衡，并受到环境温度的影响。;In order to understand the habitat utilization rule of the white-headed langur and its influencing factors, a group of white-headed langurs (Trachypithecus leucocephalus) was investigated from February 2016 to January 2017 in the Chongzuo White-headed Langur National Nature Reserve, Guangxi, China by instantaneous scanning sampling method. The results indicated that significant difference in the utilization of different limestone hill parts of white-headed langur was found (χ² =39.467, df=3, P<0.001). The cliff was used most frequently (56.75±9.55)%, followed by the slope (39.42±10.93)%, the hill-top (2.98±2.54)%, as well as the valley (0.84±1.47)%. There were significant differences in the utilization of different microhabitat types of langurs (χ²=27.709, df=3, P<0.001). Tree as the preferred microhabitat, and its percentage (49.37±12.31)% was higher than bare rock (24.05±13.61)%, liana (15.48±8.01)%, and bush (10.87±5.45)%. The langurs mainly fed on slope, and other activities, such as moving, resting and social activity were on cliff. Besides, social activity was the only behavior occurred most often in bare rock, while other behaviors occurred most often in trees. There were seasonal differences in limestone hill parts and microhabitat. In overall activities, langurs used trees significantly more in the rainy season than in the dry season (Z=-2.680, n=12, P=0.007). When feeding, langurs used slope significantly more in the rainy season than in the dry season (Z=-2.517, n=12, P=0.012), while the use of cliff was opposite (Z=-2.842, n=12, P=0.004). When resting, in the rainy season the langurs used trees significantly more than in the dry season (Z=-2.355, n=12, P=0.019). Habitat use of white-headed langurs was also influenced by temperature. The utilization frequency of overall activities of the trees increased with the average temperature (r=0.664, n=12, P=0.018). Besides, the utilization frequency of resting of the trees increased with the average temperature (r=0.650, n=12, P=0.022). In contrast, the utilization frequency of cliff and bare rock in feeding was both negatively correlated with the average temperature (cliff:r=-0.685, n=12, P=0.014; bare rock:r=-0.600, n=12, P=0.039). In different seasons, white-headed langurs used its habitat in different ways. Thus, the habitat utilization pattern of white-headed langurs may be a trade-off between feeding benefits and predation risk, and is also influenced by ambient temperature.

Climate Change and Human-Induced Environmental Promoted Speciation of Two Endangered Langurs (François' Langur and White-Headed Langur)

Climate Change and Human-Induced Environmental Promoted Speciation of Two Endangered Langurs (François' Langur and White-Headed Langur)

Variations in the gut microbiota of sympatric François’ langurs and rhesus macaques living in limestone forests in southwest Guangxi, China

Gut microbiota plays an important role in health and metabolism and is affected by diet. This means that the gut microbiota of sympatric species is different due to niche separation. In this study, high-throughput 16S rRNA sequencing was used to study the gut microbiota of sympatric François’ langurs and rhesus macaques using 57 fecal samples collected from the limestone forests of the Guangxi Chongzuo White-headed Langur National Nature Reserve. The results indicated no significant difference in gut microbial diversity between the two primate species. However, marked differences were found in gut microbial composition. François’ langurs had a greater abundance of Firmicutes, Verrucomicrobia, TM7, and Planctomycetes, and a lower abundance of Bacteroidetes, Tenericutes, Proteobacteria, WPS-2, Fibrobacteres, and Lentisphaerae than rhesus macaques. At the genus level, François’ langurs had a greater abundance of norank Ruminococcaceae, unclassified Clostridiales, norank Clostridiales, Akkermansia, and unclassified Ruminococcaceae, whereas macaques had a higher proportion of Prevotella, Coprococcus, and Oscillospira. Predictive functional analysis reveals that the gut microbiota of François’ langurs is richer in cellular processes pathways than that of rhesus macaques, which were richer in genetic information processing and organismal systems. In summary, significant differences in gut microbiota were evident between the two sympatric primate species, which is probably due to the diet separation and morphology of the digestive tract. This suggests niche separation between the sympatric limestone-dwelling rhesus macaques and François’ langurs.