Search

To fill the gap in breeding biology information about the Red-Whiskered Bulbul (Pycnonotus jocosus), in 2013, we studied the breeding biology of this species in Xishuangbanna, southwest China. The breeding began from February and continued until early August. The breeding strategy of P. jocosus was more flexible and their nests were only built in cultivated landscapes, whereas, no nest building in native tropical rain forest was found. Small open cup nests were built on 50 different plant species, and at heights ranging from 2.1±0.6 m above the ground (n=102). The mean clutch size was 2.53±0.51 eggs (n=40) and the mean egg mass was 2.81±0.25 g (n=60). The average incubation period was 11.1±0.5 days (n=14), and the average nestling period was 11.0±0.8 days (n=31). The overall nest success was 34.22%.The hatching and fledging showed either asynchrony or synchrony. Invertebrate food decreased with nestling age, whereas, plant food increased with nestling age. Moreover, distinct parental roles of the parents in nestling period were found. Compared with other passerine species, P. jocosus spent less time in incubating (58%). The clutch size, incubation and nestling period of the P. jocosus in southwest China were different from those of the P. jocosus in India.

Non-human primates often live in socially stable groups characterized by bonded relationships among individuals. Social organization can be used to evaluate living conditions and expansion potential. Bisexual group size, ratio of males to females and group composition are essential elements determining the type of social organization. Although the first report on Shortridge's capped langurs (Trachypithecus shortridgei) was in the 1970s, until now, the species only inhabits forests of the Dulongjiang valley in northwest Yunnan, China, with c. 250-370 individuals in 19 populations. To understand its social organization, we collected data from five groups of Shortridge's langurs at Silaluo in the Dulongjiang valley during August 2012-October 2013. Family groups consist of one adult male, 2-3 adult females and up to five young. Group size averaged 8 (7-9) individuals. The ratio of adult males to females (M/F) was 1:2.9, infants to adult females was (I/F) 1:2.2; and ratio of adults to immatures was 1:1.2, indicating the potential of a population increasing. Birth season was during March-July and the inter-birth interval was two years.

Seasonal variation in environmental factors is vital to the regulation of seasonal reproduction in primates. Consequently, long-term systematic data is necessary to clarify the birth seasonality and pattern of primates in highly seasonal environments. This study indicated that black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Mt. Lasha exhibited strict birth seasonality with a pulse model. Infants were born with a certain degree of synchronization. Birth distribution showed three birth peaks, and the birth pattern showed a "V" style in even-numbered years and a gradual increase in odd-numbered years. The beginning date, end date and median birth date were earlier in even-numbered years than those in odd-numbered years. The higher latitude of their habitats, earlier birth date, shorter birth period, fewer birth peaks and stronger birth synchrony might be adaptations for strongly seasonal variation in climate and food resources. After the summer solstice when daylight length began to gradually shorten, R. bieti at Mt. Lasha started to breed during the period with the highest environmental temperature and food availability, which implied that photoperiod may be the proximate factor triggering the onset of estrus and mating. It appears that R. bieti coincided conception and mid-lactation with the peak in staple foods, and weaning with the peak in high quality of foods. Thus, food availability was the ultimate factor regulating reproductive seasonality, and photoperiod was the proximate factor fine-turning the coordination between seasonal breeding and food availability.

Different types of dominance hierarchies reflect different social relationships in primates. In this study, we clarified the hierarchy and social relationships in a one-male unit of captive Rhinopithecus bieti observed between August 1998 and March 1999. Mean frequency of agonistic behaviour among adult females was 0.13 interactions per hour. Adult females exhibited a linear hierarchy with a reversal of 10.9%, indicating an unstable relationship; therefore, R. bieti appears to be a relaxed/tolerant species. The lack of a relationship between the agonistic ratio of the adult male towards adult females and their ranks indicated that males did not show increased aggression towards low-ranking females. Differentiated female affiliative relationships were loosely formed in terms of the male, and to some extent influenced by female estrus, implying that relationships between the male and females is influenced by estrus and not rank alone. A positive correlation between the agonistic ratio of adult females and their ranks showed that the degree to which one female negatively impacted others decreased with reduction in rank. Similarly, a positive correlation between the agonistic ratio of females and differences in rank suggests that a female had fewer negative effects on closely ranked individuals than distantly ranked ones. These data indicate that rank may influence relationships between females. A steeper slope of regression between the agonistic ratio and inter-female rank differences indicated that the extent of the power difference in high-ranking females exerting negative effects on low-ranking ones was larger during the mating season than the birth season, suggesting that rank may influence the mating success of females.

In this study, the quadrat method was used to study the effects of tsaoko (Fructus tsaoko) plantation on tree diversity and canopy structure of two natural habitats of eastern hoolock gibbon (Hoolock leuconedys): Nankang (characterized by extensive tsaoko plantation) and Banchang (relatively well reserved and without tsaoko plantation). Totally, 102 tree species from 25 families and 16 woody liana species from 10 families were recorded in Nankang, whereas 108 tree species from 30 families and 17 woody liana species from 12 families were recorded in Banchang. Although the tree species between two habitats is different, both habitats are characterized by enriched food resources for eastern hoolock gibbons, sharing similar dominant plant families. Due to tsaoko plantation, tree density proportion and diversity of forest layerⅠ (>20 m) in Nankang were both significantly decreased, but the tree density of layerⅡ (10-20 m) increased. Likewise, in conjunction with these behavioral observations, we also address potential impacts of tsaoko plantation on the behavior of eastern hoolock gibbon.

Food selection by folivorous primates is thought to relate to macronutrients, micronutrients and plant secondary metabolites. However, few studies explain their effects on food choices. This study was designed to clarify the effect of phytochemical components on Rhinopithecus bieti food choice by analyzing the chemical composition of food samples collected from March to May in 2010 and 2011 at Mt. Lasha in northwest Yunnan, China. Compared with non-foods, there was more phosphorous and crude protein, less total sugar and a lower ratio of calcium to phosphorus in selected foods. However, no differences were found in crude fat, crude ash, calcium and tannin content between foods and non-foods. Phytochemical constituents may influence food choices; the monkeys preferred foods with high phosphorus and low Ca/P, low calcium, low sugar and low tannins. Rhinopithecus bieti foraged high quality foods such as buds and young leaves to meet their nutritional needs after a long winter. Therefore, if tannin content in food did not exceed the enduring threshold of R. bieti, the nutrient intake was prioritized by phosphorus and calcium regulation when the need for macronutrients dominated by protein was satisfied.

Copulation patterns are important to understanding male mating strategies and stabilization strategies of social organizations in primates. However, information on copulation patterns of Asian primates is relatively rare. This study was undertaken to collect data on mating behavior and birth seasonality of Black-and-white Snub-nosed monkeys (Rhinopithecus bieti) using all occurrence sampling and Focal animal-scan sampling methods at Mt. Lasha, between January and December, 2011. Our study focused on observing mating frequency and birth rates. Snub-nosed monkeys mate year round, with two observable peaks: one reproductive peak during the mating season, roughly from August to October, and a second non-breeding peak during the birth season. It is unclear what biological significance this non-reproductive mating peak has. During our observation, we noted a lower ratio of mount to ejaculation and rare ejaculatory copulations, which indicated that every mating would not result in ejaculation. This study corroborates the previous view that the Rhinopithecus bieti's copulatory pattern is likely multiple-mount ejaculation (MME) or at the upper part of mating continuum of single-mount ejaculation (SME) toward MME. More ejaculatory copulations initiated by males than females indicate that MME is not only a mating strategy of males, but that males can influence the position of their copulatory pattern on the continuum between SME and MME. The mating frequencies significantly correlated with the birth rates with a delay of 6 to 7 months. Monkeys gave birth within a strict seasonality with a birth peak of March, which confirms the previous view. Infants were born with a certain degree of synchronization, but different populations displayed different modes of synchronizations.

Found in the Trans-Himalayas of north-west Yunnan and south-east Tibet, the black-and-white snub-nosed monkey (Rhinopithecus bieti) is one of the world's most endangered primates. A recent survey indicates that only 15 groups with 2500 individuals remain in the wild. However, the Tibetan Xiaochangdu group may be the only equilibrium group in the field since the last investigation in 1988. To evaluate the effects of traditional culture and socioeconomic activity on biodiversity conservation of R. bieti, we conducted a case study in the Honglaxueshan National Nature Reserve in southeast Tibet from June 2003 to May 2005. Interviews, direct observations, and analysis of socioeconomic data indicated major advantages to the conservation of R. bieti, which included that: 1) traditional culture mainly depended on raising livestock and collecting non-timber products rather than forest planting of Tibetan highland barley; 2) religious beliefs, against to kill any wildlife living on the sacred mountain, were mainly influenced by Tibetan Buddhism; and 3) bigger household numbers were induced by the polyandrous marriage system, which resulted in lower per capita resource consumption than smaller ones.