STAT3-induced lncRNA GNAS-AS1 accelerates keloid formation by mediating the miR-196a-5p/CXCL12/STAT3 axis in a feedback loop.

Keloids are pathological scar tissue resulting from skin trauma or spontaneous formation, often accompanied by itching and pain. Although GNAS antisense RNA 1 (GNAS-AS1) shows abnormal upregulation in keloids, the underlying molecular mechanism is unclear. The levels of genes and proteins in clinical tissues from patients with keloids and human keloid fibroblasts (HKFs) were measured using quantitative reverse transcription PCR, western blot and enzyme-linked immunosorbent assay. The features of HKFs, including proliferation and migration, were evaluated using cell counting kit 8 and a wound healing assay. The colocalization of GNAS-AS1 and miR-196a-5p in HKFs was measured using fluorescence in situ hybridization. The relationships among GNAS-AS1, miR-196a-5p and C-X-C motif chemokine ligand 12 (CXCL12) in samples from patients with keloids were analysed by Pearson correlation analysis. Gene interactions were validated by chromatin immunoprecipitation and luciferase reporter assays. GNAS-AS1 and CXCL12 expression were upregulated and miR-196a-5p expression was downregulated in clinical tissues from patients with keloids. GNAS-AS1 knockdown inhibited proliferation, migration, and extracellular matrix (ECM) accumulation of HKFs, all of which were reversed by miR-196a-5p downregulation. Signal transducer and activator of transcription 3 (STAT3) induced GNAS-AS1 transcription through GNAS-AS1 promoter interaction, and niclosamide, a STAT3 inhibitor, decreased GNAS-AS1 expression. GNAS-AS1 positively regulated CXCL12 by sponging miR-196-5p. Furthermore, CXCL12 knockdown restrained STAT3 phosphorylation in HKFs. Our findings revealed a feedback loop of STAT3/GNAS-AS1/miR-196a-5p/CXCL12/STAT3 that promoted HKF proliferation, migration and ECM accumulation and affected keloid progression.

Determinants of macaques' space use: A test for the ecological constraints model using GPS collars.

As a central topic in Behavioral Ecology, animal space use involves dynamic responses to social and ecological factors. We collared 22 rhesus macaques (Macaca mulatta) from six groups on Neilingding Island, China, and collected 80,625 hourly fixes over a year. Using this high-resolution location data set, we quantified the macaques' space use at the individual level and tested the ecological constraints model while considering various environmental and human interfering factors. As predicted by the ecological constraints model, macaques in larger groups had longer daily path lengths (DPLs) and larger home ranges. We found an inverted U-shape relationship between mean daily temperatures and DPLs, indicating that macaques traveled farther on mild temperature days, while they decreased DPLs when temperatures were too high or too low. Anthropogenic food subsidies were positively correlated to DPLs, while the effect of rainfall was negative. Macaques decreased their DPLs and core areas when more flowers and less leaves were available, suggesting that macaques shifted their space use patterns to adapt to the seasonal differences in food resources. By applying GPS collars on a large number of individuals living on a small island, we gained valuable insights into within-group exploitation competition in wild rhesus macaques.

Landscape and conservation genetics of western black crested gibbons (Nomascus concolor) in China.

Despite decades of field study, very little is known about the molecular ecology of gibbons, particularly as it relates to their ability to disperse across degraded and fragmentary landscapes. The critically endangered western black crested gibbon (Nomascus concolor) has been reduced to a small, fragmented population with about 1300 individuals. In the largest population genetic study of free-ranging gibbons to date, we sampled 47 of these gibbons from 13 sites in China and generated 15 polymorphic autosomal microsatellite markers. We identify three population clusters of N. concolor in Yunnan centered in 1) the Wuliang and Ailao Mountains, 2) the Yongde Daxueshan Mountains, and 3) an isolated remnant near the border with Vietnam. Within the Wuliang Mountains, we identified four subclusters, three of which are bounded by high-altitude rhododendron forest, and one that is isolated from the main population by ~2 km of degraded forest and pasture. Least-cost path analysis and isolation by resistance modeling demonstrates that the population genetic distances among gibbons in Wuliangshan National Nature Reserve are significantly correlated with geographic paths that avoid use of high-altitude rhododendron forest in favor of evergreen broadleaf forest. Although these gibbons have likely undergone reductions in heterozygosity from recent consanguineous mating, we suggest that their active avoidance of inbreeding on the population level maintains higher than expected levels of genetic diversity. This research provides new insights into how gibbons interact with heterogeneous environments and expands our understanding of their molecular ecology and conservation genetics.

Effects of climate and land-cover change on the conservation status of gibbons.

Species shift their distribution in response to climate and land-cover change, which may result in a spatial mismatch between currently protected areas (PAs) and priority conservation areas (PCAs). We examined the effects of climate and land-cover change on potential range of gibbons and sought to identify PCAs that would conserve them effectively. We collected global gibbon occurrence points and modeled (ecological niche model) their current and potential 2050s ranges under climate-change and different land-cover-change scenarios. We examined change in range and PA coverage between the current and future ranges of each gibbon species. We applied spatial conservation prioritization to identify the top 30% PCAs for each species. We then determined how much of the PCAs are conserved in each country within the global range of gibbons. On average, 31% (SD 22) of each species' current range was covered in PAs. PA coverage of the current range of 9 species was <30%. Nine species lost on average 46% (SD 29) of their potential range due to climate change. Under climate-change with an optimistic land-cover-change scenario (B1), 12 species lost 39% (SD 28) of their range. In a pessimistic land-cover-change scenario (A2), 15 species lost 36% (SD 28) of their range. Five species lost significantly more range under the A2 scenario than the B1 scenario (p = 0.01, SD 0.01), suggesting that gibbons will benefit from effective management of land cover. PA coverage of future range was <30% for 11 species. On average, 32% (SD 25) of PCAs were covered by PAs. Indonesia contained more species and PCAs and thus has the greatest responsibility for gibbon conservation. Indonesia, India, and Myanmar need to expand their PAs to fulfill their responsibility to gibbon conservation. Our results provide a baseline for global gibbon conservation, particularly for countries lacking gibbon research capacity.

Las especies modifican su distribución como respuesta a los cambios en el clima y el uso de suelo, lo que puede derivar en una disparidad espacial entre las áreas protegidas (AP) y las áreas de conservación prioritarias (ACP). Analizamos los efectos del cambio en el clima y el uso de suelo sobre la distribución potencial de los gibones para identificar las ACP que lograrían su conservación exitosa. Recopilamos puntos globales de presencia de gibones y modelamos (modelo de nicho ecológico) su distribución actual y potencial para la década de 2050 bajo diferentes escenarios de cambio climático y de uso de suelo. Después exploramos los cambios en la distribución y la cobertura de las AP entre la distribución actual y a futuro de cada especie de gibón y aplicamos la priorización de la conservación espacial para identificar el mejor 30% de ACP para cada especie. Posteriormente determinamos la extensión conservada de las ACP en cada país dentro de la distribución mundial de gibones. En promedio, el 31% (DS 22) de la distribución actual de cada especie está cubierta en las AP. La distribución actual de nueve especies tiene una cobertura de áreas protegidas menor al 30%. Como promedio, nueve especies perdieron el 46% (DS 29) de su rango potencial debido al cambio climático. Bajo un escenario de cambio climático con un cambio de suelo optimista (B1), doce especies perdieron el 39% (DS 28) de su distribución. Con un escenario pesimista (A2), 15 especies perdieron el 36% (DS 28) de su distribución. Cinco especies perdieron considerablemente más distribución bajo el escenario A2 en relación con el B1 (p = 0.01, SD 0.01), lo que sugiere que los gibones se beneficiarán con la gestión efectiva de la cobertura terrestre. La cobertura dentro de las AP de la distribución futura fue < 30% para once especies. En promedio, el 32% (DS 25) de las ACP estuvo cubierto dentro de las AP. Indonesia albergó más especies y más ACP, por lo que tuvo la mayor responsabilidad en la conservación de los gibones. Indonesia, India y Myanmar necesitan expandir sus AP para cumplir con su responsabilidad en la conservación de los gibones. Nuestros resultados proporcionan una línea base para la conservación mundial de los gibones, particularmente para aquellos países que carecen de los recursos para investigarlos.

Gut microbiota of skywalker hoolock gibbons (Hoolock tianxing) from different habitats and in captivity: Implications for gibbon health.

The gut microbiota plays an integral role in the metabolism and immunity of animal hosts, and provides insights into the health and habitat assessment of threatened animals. The skywalker hoolock gibbon (Hoolock tianxing) is a newly described gibbon species, and is considered an endangered species. Here, we used 16S rRNA amplicon sequencing to describe the fecal bacterial community of skywalker hoolock gibbons from different habitats and in captivity. Fecal samples (n = 5) from two captive gibbons were compared with wild populations (N = 6 gibbons, n = 33 samples). At the phylum level, Spirochetes, Proteobacteria, Firmicutes, Bacteroidetes dominated in captive gibbons, while Firmicutes, Bacteroidetes, and Tenericutes dominated in wild gibbons. At the genus level, captive gibbons were dominated by Treponema-2, followed by Succinivibrio and Cerasicoccus, while wild gibbons were dominated by Anaeroplasma, Prevotellaceae UCG-001, and Erysipelotrichaceae UCG-004. Captive rearing was significantly associated with lower taxonomic alpha-diversity, and different relative abundance of some dominant bacteria compared to wild gibbons. Predicted Kyoto Encyclopedia of Genes and Genomes pathway analyses showed that captive gibbons have significantly lower total pathway diversity and higher relative abundance of bacterial functions involved in "drug resistance: antimicrobial" and "carbohydrate metabolism" than wild gibbons. This study reveals the potential influence of captivity and habitat on the gut bacterial community of gibbons and provides a basis for guiding the conservation management of captive populations.

Disassociation of social and sexual partner relationships in a gibbon population with stable one-male two-female groups.

Adult males living in a one-male multi-female social group are expected to try to monopolize copulations with resident females to increase reproductive fitness. Gibbons have traditionally been described as living in monogamous groups, with the sole resident adult male assumed to sire all of the group's offspring. Here, we used microsatellite analyses and behavioral observations to examine rates of extra-group paternity (EGP) over 16 years in a population of crested gibbons (Nomascus concolor) that form stable and long-term one-male two-female social units. Forty percent of offspring (N = 14) were sired by extra-group males. To understand this high level of EGP, we tested whether inbreeding avoidance was related to EGP. Females who engaged in EGP did not show larger pairwise relatedness with their resident male compared to females who did not engage in EGP. Nevertheless, the standardized heterozygosity of EGP offspring was significantly higher than for offspring sired by the group's resident male. These results provide partial support for the inbreeding avoidance hypothesis. It appears that resident male crested gibbons are unable to monopolize resident females' matings. Our results indicate that long-term social partners are often distinct from sexual partners in this population. Clearly, the breeding system of crested gibbons is more flexible than previously thought, indicating a need for integrating long-term behavioral data and genetic research to re-evaluate gibbon social and sexual relationships derived from concepts of monogamy and pair-bonding.

The gut microbiota of gibbons across host genus and captive site in China.

Gut microbiota influences nutrient metabolism and immunity of animal hosts. Better understanding of the composition and diversity of gut microbiota contributes to conservation and management of threatened animals both in situ and ex situ. In this study, we applied 16S rRNA gene amplicon sequencing to evaluate the composition and diversity of the fecal bacterial community of four gibbon genera (Family Hylobatidae) at four Chinese zoos. The results showed that the dominant bacterial phyla were Bacteroidetes, Firmicutes, and Proteobacteria and dominant families were Prevotellaceae (Bacteroidetes), Spirochaetaceae (Spirochaetes) and Ruminococcaceae (Firmicutes) in the gut of all gibbons. Both captive site and host genus had significant effects on the relative abundance of dominant bacteria and structure of gut bacterial community. We found that captive site and host genus did not solely impact gut bacterial diversity, but the interaction between them did. This study provides basic knowledge for gut microbiota of all four gibbon genera and contributes to management and conservation of captive gibbons.

Effects of cold weather on the sleeping behavior of Skywalker hoolock gibbons (Hoolock tianxing) in seasonal montane forest.

Considering the high energetic costs of maintaining constant body temperature, mammals must adjust their thermoregulatory behaviors in response to cold temperatures. Although primate daytime thermoregulation is relatively well studied, there is limited research in relation to nighttime strategies. To investigate how Skywalker hoolock gibbons (Hoolock tianxing) cope with the low temperatures found in montane forests, we collected sleep-related behavior data from one group (NA) and a single female (NB) at Nankang (characterized by extensive tsaoko plantations) between July 2010 and September 2011, and one group (BB) at Banchang (relatively well-managed reserve forest) between May 2013 and May 2015 in Mt. Gaoligong, Yunnan, China. The annual mean temperature was 13.3°C at Nankang (October 2010 to September 2011) and 13.0°C at Banchang (June 2013 to May 2015) with temperatures dropping below -2.0°C at both sites, making them the coldest known gibbon habitats. The lowest temperatures at both sites remained below 5.0°C from November to March, which we, therefore, defined as the "cold season". The hoolock gibbons remained in their sleeping trees for longer periods during the cold season compared to the warm season. Sleeping trees found at lower elevations and closer to potential feeding trees were favored during cold seasons at both sites. In addition, the gibbons were more likely to huddle together during cold seasons. Our results suggest that cold temperatures have a significant effect on the sleeping behavior of the Skywalker hoolock gibbon, highlighting the adaptability of this threatened species in response to cold climates.

Influence of food availability and climate on behavior patterns of western black crested gibbons (Nomascus concolor) at Mt. Wuliang, Yunnan, China.

Food abundance and climatic factors can significantly affect the behavior of animals and constrain their activity budgets. The population of western black crested gibbons (Nomascus concolor) in Mt. Wuliang lives in montane forest and is close to the northern extreme of the distribution for gibbons (Hylobatidae). Their habitats show remarkable seasonal variation in terms of food availability, temperature, and rainfall. To understand behavioral adaptations of western black crested gibbons to different sets of ecological conditions, we examined relationships among food availability, mean temperature, rainfall, and behavior patterns by observing two groups for 1 year each. Our results revealed that activity budget was affected by food availability and mean temperature. The gibbons spent more time eating flowers when that resource was more available and spent less time moving when fruit was more available. The gibbons spent less time feeding and more time resting, and spent less feeding time on fruit and leaves when the mean temperature was lower. These results suggest that the gibbons displayed a pronounced preference for flowers as a food resource and adopted a time minimizer strategy when high-nutrient food items (i.e., fruit) were more available. In addition, the gibbons adopted an energy-conserving strategy during periods of low temperature. The flexibility of behavioral patterns in responding to food availability and temperature may potentially improve the gibbons' prospects of surviving and reproducing in a northern montane forest.

Infant loss during and after male replacement in gibbons.

According to the sexual selection hypothesis, infanticide during resident male replacement is an adaptive strategy that has evolved because the killing of unweaned offspring sired by previous males shortens the inter-birth intervals of the mothers whose infants are targeted and thereby increases the reproductive fitness of the perpetrator. To test this hypothesis, we describe previously unreported cases of primary male replacement for two gibbon species (Hylobates lar and Nomascus nasutus), and review all other reported cases of primary male replacement in gibbons. Overall, infants were present in nearly half of all cases (16/33, 48%) and of the 18 infants present during replacement, 50% (N = 9) disappeared within 2 months of the event. In four of the five cases where there was sufficient demographic information to identify the likely sire of the subsequent offspring of females that lost infants, the new male was believed to be the sire. Infants were also less likely to die or disappear if the new male and original resident male were possible kin. However, there was no significant difference in the age of infants between those that died or disappeared following replacement and those that survived to weaning (p = .630). Our review of takeover-related infant loss in gibbons confirms that periods of male instability are risky for unweaned infants and that replacing males benefit from infant loss. Nevertheless, variability in the context of infant loss and difficulties related to data collection in the field make it difficult to test competing hypotheses concerning the mechanisms and functions of infanticide in the small apes.

Diet and feeding behavior of a group of 42 Phayre's langurs in a seasonal habitat in Mt. Gaoligong, Yunnan, China.

In habitats such as temperate evergreen forests, fruit, and seed productivity is reported to exhibit marked changes in seasonal availability, such that fruit is most available in summer and seeds are most available in autumn. Primates living in these habitats, therefore, are expected to adjust their diets in response to the spatial and temporal variation in these food resources. We studied the diet and feeding behavior of a group of 42 Phayre's langurs (Trachypithecus phayrei) living in a northern (24°48'N) montane habitat (1,700-2,350 m) in Mt. Gaoligong, Yunnan, China from August 2012 to July 2013. The langurs were found to forage on 50 plant species, of which 28 species each accounted for more than 1% of their annual feeding time. Castanopsis echidnocarpa, the most abundant species in their habitat, accounted for 17.5% of the total forest trees, and contributed to the largest proportion of the annual langur diet. The primary component of the langur diet was composed of fruits (22.2%), seeds (18.7%), and buds and young leaves (41.5%). Mature leaves accounted for only 4.1% of their diet. Based on DBH and the percent of the crown containing edible food items, we found that the langurs changed their monthly diet according to the availability of fruits and seeds (Spearman rank correlation: r = 0.609, p = 0.035), and buds and young leaves (Spearman rank correlation: r = 0.837, p = 0.001). The seeds of C. echidnocarpa accounted for 12.5% of langur feeding time. A single tree produced a large seed and fruit crop, which likely reduced opportunities for within-group feeding competition. We argue that the resource productivity of this northern montane enables Phayre's langurs to live in stable groups that are 3.6 times larger than reported for Phayre's langurs living in other habitats.

Description of a new species of Hoolock gibbon (Primates: Hylobatidae) based on integrative taxonomy.

We describe a species of Hoolock gibbon (Primates: Hylobatidae) that is new to science from eastern Myanmar and southwestern China. The genus of hoolock gibbons comprises two previously described living species, the western (Hoolock hoolock) and eastern hoolock (H. leuconedys) gibbons, geographically isolated by the Chindwin River. We assessed the morphological and genetic characteristics of wild animals and museum specimens, and conducted multi-disciplinary analyses using mitochondrial genomic sequences, external morphology, and craniodental characters to evaluate the taxonomic status of the hoolock population in China. The results suggest that hoolocks distributed to the east of the Irrawaddy-Nmai Hka Rivers, which were previously assigned to H. leuconedys, are morphologically and genetically distinct from those to the west of the river, and should be recognized as a new species, the Gaoligong hoolock gibbon or skywalker hoolock gibbon (H. tianxing sp. nov.). We consider that the new species should be categorized as Endangered under IUCN criteria. The discovery of the new species focuses attention on the need for improved conservation of small apes, many of which are in danger of extinction in southern China and Southeast Asia.

Effects of group density, hunting, and temperature on the singing patterns of eastern hoolock gibbons (Hoolock leuconedys) in Gaoligongshan, Southwest China.

Many non-human primates produce species-specific loud calls to communicate within and between groups over long distances. Understanding these calling patterns can provide insights into how individuals modify their behavior in response to environmental variables as well as help to design efficient bioacoustic survey techniques. Eastern hoolock gibbons in Gaoligongshan inhabit the coldest habitat of all gibbon populations, but both conservation and research efforts on this population have been minimal. We studied singing patterns of two habituated and two unhabituated groups at two sites in Gaoligongshan between July 2010 and June 2015. We systematically collected data of their calls, and its relationship to temperature, group density, and hunting pressure over at least 1 year for each group. Our goal was to elucidate how these factors affect singing patterns of eastern hoolock gibbons. We found that adult pairs coordinated their singing to produce duet bouts that lasted for an average of 25.5 min. The singing rate (number of bouts/number on monitoring days*100%: 7.5-31.4%) was notably lower than other gibbon populations, presumably due to low group density (about 0.5 groups/km(2) ) and prevalence of hunting at the study site. Cold temperature also affected gibbons' singing behavior. Our study groups called, on average, 2.5 hr after sunrise, probably foraging first in the early morning after long nights in this cold habitat delayed singing. Furthermore, mean temperatures in the morning (8:00-12:00 am) were higher on singing days than on non-singing days, and one group called less frequently when monthly mean temperature was below 10°C. Our findings indicate that both hunting pressure from humans and low temperatures suppress calling behavior in hoolock gibbons. Such information is critical in evaluating the use of duetting as a monitoring technique for this endangered gibbon species. Am. J. Primatol. 78:861-871, 2016. © 2016 Wiley Periodicals, Inc.

Understanding stable bi-female grouping in gibbons: feeding competition and reproductive success.

INTRODUCTION: Species of the order Primates are highly gregarious with most species living in permanent heterosexual social groups. According to theory in socioecology maximum social group size is limited by rates of intra-group feeding competition and associated increases in travel costs. Unlike other hylobatids, which are predominantly pair living, cao vit gibbons (Nomascus nasutus), and two other species of crested gibbon (Nomascus spp.) living in northern seasonal forest, regularly exhibit larger bi-female groups. To better understand the ability of northern gibbons to live in stable bi-female groups, we examined food distribution, feeding competition and reproductive success over a period of six years in a small cao vit gibbon population at Bangliang, Guangxi, China. RESULTS: In general, we found weak evidences for within-group contest or scramble competition in our two study groups, which we attribute to high spatial and temporal heterogeneity in the distribution of their important food species. Nevertheless, the larger of the two groups studied increased feeding time and group spread during lean periods, factors that may limit cao vit gibbon group size to a maximum of two breeding females. Relative to tropical pair-living gibbons, there is no evidence that cao vit gibbons travel farther or spend more time feeding, but they did consume more leaves and buds and less fruit and figs. Despite their highly folivorous diet, the average inter-birth interval is comparable to tropical gibbon populations, and the survival rate of infants and juveniles in our study groups is high. CONCLUSION: Cao vit gibbons do not suffer obvious costs in terms of feeding competition and reproductive success by living in bi-female groups, but within-group feeding competition may determine the upper the limit of cao vit gibbon group size to a maximum of two breeding females. These findings contribute to a growing body of evidence that bi-female grouping can be a stable grouping pattern of gibbons in certain habitats and further emphasize the flexibility of gibbon social organization.

White-cheeked macaque (Macaca leucogenys): A new macaque species from Medog, southeastern Tibet.

We describe a newly discovered Macaca species from the Medog, in southeastern Tibet, China, Macaca leucogenys sp. nov or the "white-cheeked macaque". Based on 738 photos taken during direct observations and captured by camera traps this new species appears to be distinct from the Macaca sinica species group. Moreover, the species is distinguished from all potential sympatric macaque species (M. mulatta, M. thibetana, M. assamensis, and M. munzala) in exhibiting a suite of pelage characteristics including relatively uniform dorsal hair pattern, hairy ventral pelage, relative hairless short tail, prominent pale to white side- and chin-whiskers creating a white cheek and round facial appearance, dark facial skin on the muzzle, long and thick hairs on its neck, and a round rather than arrow-shaped male genitalia. This new macaque species was found to exploit a diverse set of habitat types from tropical forest at 1395 m, to primary and secondary evergreen broad-leaved forest at 2000 m, as well as mixed broadleaf-conifer forest at 2700 m. Its range may extend to neighboring counties in Tibet and the part of southeastern Tibet controlled by India. The white-cheeked macaque is threatened by illegal hunting and the construction of hydropower stations. Discovery of this new primate species further highlights the high value for biodiversity conservation of southeastern Tibet and calls for more intensive surveys, studies, and environmental protection in this area.

Eco-evolutionary dynamics of gut phageome in wild gibbons (Hoolock tianxing) with seasonal diet variations.

It has been extensively studied that the gut microbiome provides animals flexibility to adapt to food variability. Yet, how gut phageome responds to diet variation of wild animals remains unexplored. Here, we analyze the eco-evolutionary dynamics of gut phageome in six wild gibbons (Hoolock tianxing) by collecting individually-resolved fresh fecal samples and parallel feeding behavior data for 15 consecutive months. Application of complementary viral and microbial metagenomics recovers 39,198 virulent and temperate phage genomes from the feces. Hierarchical cluster analyses show remarkable seasonal diet variations in gibbons. From high-fruit to high-leaf feeding period, the abundances of phage populations are seasonally fluctuated, especially driven by the increased abundance of virulent phages that kill the Lachnospiraceae hosts, and a decreased abundance of temperate phages that piggyback the Bacteroidaceae hosts. Functional profiling reveals an enrichment through horizontal gene transfers of toxin-antitoxin genes on temperate phage genomes in high-leaf season, potentially conferring benefits to their prokaryotic hosts. The phage-host ecological dynamics are driven by the coevolutionary processes which select for tail fiber and DNA primase genes on virulent and temperate phage genomes, respectively. Our results highlight complex phageome-microbiome interactions as a key feature of the gibbon gut microbial ecosystem responding to the seasonal diet.

Vocal fingerprinting reveals a substantially smaller global population of the Critically Endangered cao vit gibbon (Nomascus nasutus) than previously thought.

The cao vit gibbon (Nomascus nasutus) is one of the rarest primates on Earth and now only survives in a single forest patch of less than 5000 ha on the Vietnam-China border. Accurate monitoring of the last remaining population is critical to inform ongoing conservation interventions and track conservation success over time. However, traditional methods for monitoring gibbons, involving triangulation of groups from their songs, are inherently subjective and likely subject to considerable measurement errors. To overcome this, we aimed to use 'vocal fingerprinting' to distinguish the different singing males in the population. During the 2021 population survey, we complemented the traditional observations made by survey teams with a concurrent passive acoustic monitoring array. Counts of gibbon group sizes were also assisted with a UAV-mounted thermal camera. After identifying eight family groups in the acoustic data and incorporating long-term data, we estimate that the population was comprised of 74 individuals in 11 family groups, which is 38% smaller than previously thought. We have no evidence that the population has declined-indeed it appears to be growing, with new groups having formed in recent years-and the difference is instead due to double-counting of groups in previous surveys employing the triangulation method. Indeed, using spatially explicit capture-recapture modelling, we uncovered substantial measurement error in the bearings and distances from field teams. We also applied semi- and fully-automatic approaches to clustering the male calls into groups, finding no evidence that we had missed any males with the manual approach. Given the very small size of the population, conservation actions are now even more urgent, in particular habitat restoration to allow the population to expand. Our new population estimate now serves as a more robust basis for informing management actions and tracking conservation success over time.

Gut microbiome responds compositionally and functionally to the seasonal diet variations in wild gibbons.

Wild animals may encounter multiple challenges especially food shortage and altered diet composition in their suboptimal ranges. Yet, how the gut microbiome responds to dietary changes remains poorly understood. Prior studies on wild animal microbiomes have typically leaned upon relatively coarse dietary records and individually unresolved fecal samples. Here, we conducted a longitudinal study integrating 514 time-series individually recognized fecal samples with parallel fine-grained dietary data from two Skywalker hoolock gibbon (Hoolock tianxing) groups populating high-altitude mountainous forests in western Yunnan Province, China. 16S rRNA gene amplicon sequencing showed a remarkable seasonal fluctuation in the gibbons' gut microbial community structure both across individuals and between the social groups, especially driven by the relative abundances of Lanchnospiraceae and Oscillospiraceae associated with fluctuating consumption of leaf. Metagenomic functional profiling revealed that diverse metabolisms associated with cellulose degradation and short-chain fatty acids (SCFAs) production were enriched in the high-leaf periods possibly to compensate for energy intake. Genome-resolved metagenomics further enabled the resolving metabolic capacities associated with carbohydrate breakdown among community members which exhibited a high degree of functional redundancy. Our results highlight a taxonomically and functionally sensitive gut microbiome actively responding to the seasonally shifting diet, facilitating the survival and reproduction of the endangered gibbon species in their suboptimal habitats.

Phylogenomic analyses provide insights into primate evolution.

Comparative analysis of primate genomes within a phylogenetic context is essential for understanding the evolution of human genetic architecture and primate diversity. We present such a study of 50 primate species spanning 38 genera and 14 families, including 27 genomes first reported here, with many from previously less well represented groups, the New World monkeys and the Strepsirrhini. Our analyses reveal heterogeneous rates of genomic rearrangement and gene evolution across primate lineages. Thousands of genes under positive selection in different lineages play roles in the nervous, skeletal, and digestive systems and may have contributed to primate innovations and adaptations. Our study reveals that many key genomic innovations occurred in the Simiiformes ancestral node and may have had an impact on the adaptive radiation of the Simiiformes and human evolution.

Behavioral responses of Cao Vit gibbon (Nomascus nasutus) to variations in food abundance and temperature in Bangliang, Jingxi, China.

The Cao Vit gibbon is a critically endangered species with only about 110 individuals remaining in a degraded karst forest along the China-Vietnam border. Behavioral data from this site are particularly useful in understanding gibbon behavioral adaptations to different sets of ecological conditions and will contribute to the conservation of the species. We studied seasonal variation in the time budget and diet of the Cao Vit gibbon in response to variation in food availability and ambient temperature by observing two groups for 1,379 hr between January and December 2009. We used 5-min scan samples to record the activity of gibbons. Both ambient temperature and food availability varied from month to month. Gibbon groups increased resting time and huddled together in sleeping places in cold months. Gibbons spent more time feeding on fruit when fruit was more abundant suggesting that fruit was their preferred food. Alternatively, leaf eating was negatively correlated with leaf availability which suggested that leaves may be used as a fallback food. Gibbons increased their diet diversity when they ate more leaves. This might be a strategy to cope with toxins or digestion inhibitor accumulation associated with feeding from a limited number of leaf species. Individuals consumed more buds when Broussonetia papyrifera produced buds in March and April. During this period, they decreased traveling time and engaged in less frequent social interactions. Gibbons spent more time searching for and feeding on invertebrates during June and October. However, we did not collect data on invertebrate abundance and therefore cannot determine the relationship between invertebrate feeding and availability. We conclude that flexibility in consuming diverse food types and food species, and in responding to the availability of preferred foods, has enabled the Cao Vit gibbon to survive in a degraded karst forest habitat.