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Abstract The issue of poor sexual performance of some male giant pandas seriously impairs the growth and the genetic diversity of the captive population, yet there is still no clear understanding of the cause of the loss of this ability and its underlying mechanism. In this study, we analyzed the gut microbiota and its function in 72 fecal samples obtained from 20 captive male giant pandas, with an equal allocation between individuals capable and incapable of natural mating. Additionally, we investigated fecal hormone levels and behavioral differences between the two groups. A correlation analysis was then conducted among these factors to explore the influencing factors of their natural mating ability. The results showed significant differences in the composition of gut microbiota between the two groups of male pandas. The capable group had significantly higher abundance of Clostridium sensu stricto 1 (padjusted = .0021, GLMM), which was positively correlated with fatty acid degradation and two‐component system functions (Spearman, padjusted

Reintroduction plays a vital role in conservation for many endangered species, however, little long-term information is available on the population dynamics and conservation status. Here we provide a detailed account of the Chinese Milu (Elaphurus davidianus) conservation and reintroduction efforts over the past 35 years, and give updated information on current Milu distribution, population dynamics and conservation status based on long-term monitoring (1985–2020) and a detailed follow-up investigation (2013–2020) in 235 wildlife institutions throughout China. Milu conservation in China comprised three phases: i) establishing ex situ populations and increasing the number of Milu through captive breeding (1985–1992); ii) preparing captive Milu for life in the wild and establishing in situ conservation populations (1993–1997); and iii) reintroduction of Milu into the wild throughout their historic range (1998–ongoing). Currently, there are ca. 9062 Milu (including 2825 wild individuals) distributed across 83 sites with 7380 individuals living at Beijing Milu Park, Jiangsu Dafeng Milu Nature Reserve and Hubei Shishou Milu Nature Reserve. The average birth rates in three sites were all over 0.200, and the average adult mortality rates were below 0.085, resulting in a rapid population growth. We discuss a variety of factors that contributed to ex situ conservation success in the reintroduction of a species formerly extinct in the wild, and highlight past and present challenges of Milu conservation in China. Our results will provide helpful information on conservation and reintroduction for other endangered species around the world.

Mammal gastrointestinal tracts harbor diverse bacterial communities that play important roles in digestion, development, behavior, and immune function. Although, there is an increasing understanding of the factors that affect microbial community composition in laboratory populations, the impact of environment and host community composition on microbiomes in wild populations is less understood. Given that the composition of bacterial communities can be shaped by ecological factors, particularly exposure to the microbiome of other individuals, inter-specific interactions should impact on microbiome community composition. Here, we evaluated inter-population and inter-specific similarity in the fecal microbiota of Przewalski’s gazelle (Procapra przewalskii), an endangered endemic ruminant around Qinghai Lake in China. We compared the fecal bacterial communities of three Przewalski’s gazelle populations, with those of two sympatric ruminants, Tibetan gazelle (Procapra picticaudata) and Tibetan sheep (Ovis aries). The fecal bacterial community richness (Chao1, ACE) did not vary across the three Przewalski’s gazelle populations, nor did the composition vary between species. In contrast, the managed Przewalski’s gazelle population had higher bacterial diversity (Shannon and Simpson) and was more similar to its sympatric Tibetan sheep in beta diversity than the wild Przewalski’s gazelle populations. These results suggest that ecological factors like host community composition or diet affect Przewalski’s gazelle’s gastrointestinal bacterial community. The role of bacterial community composition in maintaining gastrointestinal health should be assessed to improve conservation management of endangered Przewalski’s gazelle. More broadly, captive breeding and reintroduction efforts may be impeded, where captive management results in dysbiosis and introduction of pathogenic bacteria. In free ranging populations, where wildlife and livestock co-occur, infection by domestic pathogens and diseases may be an underappreciated threat to wild animals.

The giant panda (Ailuropoda melanoleuca) has evolved a large number of mucous glands in the intestinal lining to adapt to the digestion of high-fiber foods. However, in captive pandas, excessive mucus might form a mass and then be eliminated, which is often accompanied by discomfort and decreased activity. This event is called ‘mucous excretion’. The causes of mucus excretions in captive pandas, however, remain unknown. The aims of this study were to document the occurrence of mucus excretion and to investigate its possible associations with pandas’ age, gender, and feces output. Eighteen giant pandas were studied at the Beijing Zoo from April 2003 to June 2017, and a total of 900 occurrences of mucous excretion and 32,856 daily defecation outputs in weight were recorded. The likelihood of mucous excretion occurrence decreased by 11.34% for each 1 kg of fecal output (Z = −4.12, p < 0.0001), while it increased by 5.89% per year of age (Z = 4.02, p < 0.0001). However, individual differences in gender had no significant effect on the mucous occurrence (Z = −0.75, p = 0.4508). A monthly change in mucus occurrence was also found. The mean frequency of mucus occurrence was significantly higher in October. In August, time (month) change showed the biggest negative influence on feces output but the biggest positive influence on mucus excretion (seasonal factors were −2.261 and 0.0126, respectively). Our results documented the occurrence of mucous excretions and confirmed their possible associations with the pandas’ age and fecal output based on a 15-year prospective study. This study not only adds to our knowledge of panda physiology but also suggests the need for further studies examining the causes of the excretion of mucous stools in captive pandas. Reducing the incidence of mucous excretion would promote ex situ conservation and enhance panda welfare.

It has been documented that social isolation imparts deleterious effects on gregarious rodents species, but caging in group imparts such effects on solitary rodents. This study was attempted at examining how kinship to affect body weight, behavioral interaction, mate choice and fitness when we caged male and female rat-like hamsters Tscheskia triton in pair, a solitary species. We found that females paired with nonsibling males became heavier than the females paired with sibling males, but both agonistic and amicable behavior between paired males and females did not differ between sibling and nonsibling groups. This indicated that kinship might reduce females’ obesity in response to forced cohabitation, and dissociation might exist between physiological and behavioral responses. Furthermore, binary choice tests revealed that social familiarity between either siblings or nonsiblings decreased their investigating time spent in opposite sex conspecific of cage mates and/or their scents as compared with those of non-mates, suggesting effects of social association on mate and kin selection of the hamsters. On the other side, both females and males caged in pair with siblings show a preference between unfamiliar siblings or their scents and the counterparts of nonsiblings after two month separation, indicating that the kin recognition of the hamsters might also rely on phenotype matching. In addition, cohabitation (or permanent presence of fathers) elicited a lower survival of pups in nonsibling pairs than sibling pairs, but did not affect litter size, suggesting that kinship affects fitness when housing male and female ratlike hamsters together. Therefore, inbreeding might be adapted for rare and endangered animals [Current Zoology 55(1): 41–47, 2009].

The scent of a novel male can elicit pregnancy block in recently mated female mice (Mus musculus), a phenomenon known as the Bruce effect. Despite abundant literature on the Bruce effect in rodents, it remains unclear whether males related to a female's original mate can induce the Bruce effect in out-bred, communally living mice. We investigated this question using Kunming (KM) male mice of varying genetic relatedness. Recently mated females were subjected to three treatments: exposure to the urine of the mate, urine of the mate's male littermate, and urine of a male unrelated to the mate. It was found that the urine of male littermates of the females' mates did not elicit more pregnancy block than that of the females' mates. However, the urine of novel males caused a higher rate of female miscarriage than that of the females' mates. By using a habituation-dishabituation paradigm, we found that unmated females could discriminate the urine scents of two male littermates from those of a novel male unrelated to the littermates. To understand how females use urinary cues to discriminate between males with different genetic relationships, we used gas chromatography coupled with mass spectrometry (GC-MS) to examine the volatile composition of urine from males with varying relatedness. It was found that KM male littermates shared similar volatile compositions in their urine. Our results suggest that male kinship reduces the Bruce effect in female KM mice, and provide additional evidence for mate choice being partly mediated by the Bruce effect in KM mice.

Males will alter their mating behavior to cope with the presence of their competitors. Even exposure to odors from potential competitors can greatly increase male ejaculate expenditure in a variety of animals including insects, fishes, birds and rodents. Major efforts have been made to examine males' plastic responses to sperm competition and its fitness benefits. However, the effects of competitor absence on male's sexual motivation and behaviors remain unclear, which has been proposed to be one of the causes for the poor sexual performance of some captive mammals. This study revealed that sexual motivation can be greatly enhanced in captive male giant pandas (Ailuropoda melanoleuca) by exposure to chemosensory cues from either one or three conspecifics males. It had been shown that potential rivals' odors increased males' chemosensory investigation behavior, as well as their observing, following and sniffing behaviors towards estrous females. Behaviors changed regardless of the number of rivals (one or three). Our results demonstrate the effects of potential competition on male giant pandas' sexual motivation and behavioral coping strategy. We anticipate that our research will provide a fresh insight into the mechanisms underlying poor sexual performance in male captive mammals, and valuable information for the practical management and ex situ conservation of endangered species.

Giant panda Ailuropoda melanoleuca exhibits are popular attractions for zoos and wildlife parks. However, it remains to be investigated whether such exhibits enhance visitor knowledge about pandas and broader conservation issues. We conducted questionnaire surveys at giant panda exhibits at three city zoos and five wildlife parks in China. Although visitors were generally interested in the giant panda, this was not reflected in their post-exhibit knowledge of giant panda biology. Socio-demographically, men were more knowledgeable of giant panda biology than women. Knowledge correlated positively with respondent level of education. Younger respondents (< 45 years) knew most about giant pandas and expressed an interest in learning more about them using social media. The most informed respondents had visited other giant panda exhibits previously. Respondents were generally satisfied with the giant panda exhibits (mean score 4.44/5). Wildlife parks delivered a better educational outcome than city zoos. We recommend approaches to improve the visitor experience further and to leverage public interest in broader conservation engagement and action in China.

The article examines the 13 indicators used by local governments in China to assess environmental impacts of township and village enterprises (TVEs). These include atmospheric pollution coefficients, ratio of runoff to wastewater, TVE technical advancements, coal consumption density, TVE economic density, and percent of forest cover.

The giant panda Ailuropoda melanoleuca belongs to the family of Ursidae; however, it is not carnivorous, feeding almost exclusively on bamboo. Being equipped with a typical carnivorous digestive apparatus, the giant panda cannot get enough energy for an active life and spends most of its time digesting food or sleeping. Feeding and mating are both regulated by odors and pheromones; therefore, a better knowledge of olfaction at the molecular level can help in designing strategies for the conservation of this species. In this context, we have identified the odorant-binding protein (OBP) repertoire of the giant panda and mapped the protein expression in nasal mucus and saliva through proteomics. Four OBPs have been identified in nasal mucus, while the other two were not detected in the samples examined. In particular, AimelOBP3 is similar to a subset of OBPs reported as pheromone carriers in the urine of rodents, saliva of the boar, and seminal fluid of the rabbit. We expressed this protein, mapped its binding specificity, and determined its crystal structure. Structural data guided the design and preparation of three protein mutants bearing single-amino acid replacements in the ligand-binding pocket, for which the corresponding binding affinity spectra were measured. We also expressed AimelOBP5, which is markedly different from AimelOBP3 and complementary in its binding spectrum. By comparing our binding data with the structures of bamboo volatiles and those of typical mammalian pheromones, we formulate hypotheses on which may be the most relevant semiochemicals for the giant panda. [ABSTRACT FROM AUTHOR]

The main and accessory olfactory systems of mammals are involved in the detection of predator odor; however, the relative importance assigned to each varies between studies. We examined the behavioral responses of vomeronasal organ removed (VNOx) and sham operated (VNOi) female golden hamsters (Mesocricetus auratus) to urine odor from a predator, the ferret (Mustela putorius furo). We quantified the duration and frequency of the defensive behaviors vigilant rearing and concealment, and the neutral behaviors grooming and investigation, in female golden hamsters in a visible burrow system. We found that VNOx females exposed to predator urine odor spent significantly less time in concealment and more time rearing than VNOi females. Further experiments in which females were exposed to formaldehyde odor showed that their behavioral responses to ferret odor differed from those to formaldehyde odor. This shows that the female hamsters' behavioral responses are not adverse reactions to noxious odors, but typical reactions to predators. Golden hamsters have been laboratory-reared for over 80 years, but defensive behavior in females appears to be innate and can be impaired by surgical removal of the vomeronasal organ. Therefore, the accessory olfactory system, via the vomeronasal organ, plays a role in the detection of predator odor by golden hamsters, even though it has not been found to function in conspecific odor discrimination. [ABSTRACT FROM AUTHOR]

Wild animals are affected by growing human interference in their habitats and inevitably react inter-nally to such stimuli. This study explores inherent physiological parameters to assess the effect of human interference on giant pandas in their wild habitat. Ninety-one fecal samples were collected within four nature reserves on Qinling Mountain. Fecal Cortisol determinations were performed by ra-dioimmunoassay. We categorized the intensity of local human disturbance and tested for correlations between the intensity of human disturbance and fecal Cortisol metabolite levels. The results show a significant positive correlation between giant panda fecal Cortisol metabolite levels and the degree of disturbance in their habitat. This study is the first to use a non-invasive monitoring method to analyze wild giant panda habitat disturbance, and demonstrates that Cortisol metabolite levels in panda dung can objectively reflect the degree of panda habitat disturbance. The results provide a relatively ob-jective means and method with which to evaluate the quality of wild giant panda habitat. This study highlights the need to monitor the effects of human disturbance on wildlife and to implement new policies in the management of nature reserves. [ABSTRACT FROM AUTHOR]

Chemical communication plays an important role in kin selection and mate choice in mammals. The covariance of odor-genes of rodents has been documented and kinship odor has been proposed and termed, yet little is known of the relationship between genetic relatedness and chemical composition of kinship odors. Giant pandas (Alluropoda melanoleuca) rely substantially on chemical communication to mediate their social interactions. To examine the relationship between genetic relatedness and compounds in the urine/anogenital gland secretions, we compared the similarities between genetic relatedness and the chemical profiles of anogenital gland secretions and urine via lineage construction and GC-MS (gas chromatography and mass spectrometry). We found that information about kinship odors was present only in the urine of male adults in the mating season but absent in the non-mating season. Adult females and all sub-adults did not have such kinship odors in either mating or non-mating season. Therefore, kinship odor in the panda was contingent on age, sex, and season. This is the first report about the condition-dependent expression of kinship odor, which may have a significant implication in the practice of panda conservation in relation to chemical communication and sexual selection. [ABSTRACT FROM AUTHOR]

Abstract  With a combination of dichloromethane extraction and analysis by gas chromatography–mass spectrometry (GC-MS), we found 39 compounds (corresponding to 38 GC peaks) in the anogenital gland secretion (AGS) of captive adult giant pandas, Ailuropoda melanoleuca, during the non-mating season. In addition to indole, squalene, and some of the straight-chain fatty acids that had been characterized previously from the AGS of giant pandas, we identified several new compounds such as decenal, two isomers of decadienal, phenylacetic acid, 5-methylhydantoin, hydroquinone, phenylpropanoic acid, and erucic acid. Quantitative comparison of the relative abundances of the 20 main GC peaks revealed that 5-methylhydantoin, indole, and erucic acid are putative female pheromones, whereas squalene and hydroquinone are putative male pheromones. In addition to the presence of a few individual-specific compounds, the relative abundances of most of the 21 constituents varied more among individuals than within individuals. This suggests that individual identity might be coded in both digital and analog form. The chemical composition of different AGS samples from the same pandas consistently displayed a minimum cluster distance, much smaller than that between samples from different individuals in a hierarchical linkage cluster (average linkage) dendrogram. Our results indicate that the AGS might contain an “odor fingerprint.” Although putative sex pheromones such as squalene and erucic acid should be assessed further by bioassay, our study suggests that synthetic chemosignals might be useful in modulating the behavior and physiology of giant pandas. [ABSTRACT FROM AUTHOR]

Anogenital gland secretions play a major role in chemical communication by giant pandas, Ailuropoda melanoleuca (David, 1869). We analyzed 45 samples of anogenital gland secretions collected from 24 captive pandas (5 male adults, 6 female adults, 6 male subadults, and 7 female subadults) by gas chromatography and mass spectrometry. The secretions contained over 95 compounds. Based on 56 common compounds (relative abundances >0.1%) shared by more than three individuals, we identified steroids, long-chain fatty acids, fatty-acid esters, aldehydes, alkanes, alkenes, amines, terpenes, and furans. The chemical composition of each secretion was individual-specific. Although none of these individual compounds was age- or sex-specific, the relative abundances of several compounds differed between males and females and between adults and subadults. This result shows that information about sex and age could be coded in analog form. Information about age but not gender could also be digitally coded by the presence or absence of some of the 56 compounds, in addition to the analog coding. [ABSTRACT FROM AUTHOR]