Group living provides various advantages to individuals in regards to protection avoidance,intergroup competition,productive success and social information.Stable one-male units(OMUs)consist of relationships between the adult females and the resident male as well as the relationships among adult females.Based on continuous observation of a reproductive group of golden snub-nosed monkeys(Rhinopithecus roxellana)in the Qinling Mountains,we analyzed the relationships among adult individual dyads within 4 OMUs.The results indicated that in golden snub-nosed monkey societies,females not only had no strong tendency to build a relationship with the resident male in the OMU but also had no strong tendency to build relationships with other females in the OMU.In comparison with hamadryas(Papio hamadryas)and gelada baboons(Theropithecus gelada),the relationships within golden snub-nosed monkeys OMUs showed neither the star-shaped pattern observed in hamadryas baboons nor the net-shaped pattern observed in gelada baboons.We concluded that the relationships within golden snub-nosed monkey OMUs indicated a third pattern in nonhuman primate societies.Future research is required to determine the potential mechanisms for such a pattern.
Xiaowei WANGChengliang WANGXiaoguang QISongtao GUOHaitao ZHAOBaoguo LI
Molecular studies using trace DNA, such as from museum specimens, ancient or forensic samples and samples obtained noninvasively, often have a common problem of low quality of DNA templates. Amplification errors, such as allelic dropout and false allele, may arise during polymerase chain reaction (PCR) using such samples. A mathematical model which treats homozygotes and heterozygotes discriminately has been developed to measure sample quality and compute the confidence level of using multipletube approaches. We use plucked hair samples collected from 26 individual Sichuan snub-nosed monkeys (Rhinopithecus roxel- lana) to test the model. In this case, a confidence level of 99% can be achieved by three positive PCRs. If the sample quality is very poor and requires many PCR replicates, an alternative multiplestep genotyping method is recommended. This model enables researchers to optimize experimental protocols through pilot studies and obtain reliable genetic information using noninvasive sampling method.
HE GangiHUANG KangGUO SongTaoJI WeiHongQI XiaoGuangREN YiJIN XueLinLI BaoGuo
We studied the responsiveness of the Sichuan snub-nosed monkey Rhinopithecus roxellana, an arboreal Old World monkey, to the presence of novel stimuli associated with familiar food. We also determined differences in responses by age and sex. Results showed that monkeys exhibited neophilia and neophobia simultaneously when facing novel stimuli. Age affected the response to novel stimuli significantly, with immature individuals responding to novel stimuli most frequently and infants least frequently. No significant differences were observed for sex, although females were more responsive to the novel object than were males. Our results support the ＂readiness to eat＂ hypothesis that the presence of a novel object can increase latencies to consume familiar food .
Weiwei FUDapeng ZHAOXiaoguang QISongtao GUOWei WEIBaoguo LI
For group-living primates, the information on postconflict management is crucial for understanding primate competition and cooperation. However, such information is poorly known for snub-nosed monkeys, especially for wild populations. In this study, from September 2007 to June 2008, we investigated postconflict behavior among adult females Sichuan snub-nosed monkeys Rhinopithecus roxellana within one-male units in a wild, provisioned group in the Qinling Mountains of China by means of the time-rule method and the PC-MC method. We obtained a total of 81 PC-MC pairs and each individual was involved in only 0.004 aggressive behavior per observation hour. The first affiliative behavior was more likely to occur within the first minute after a conflict. The postconflict affiliative behaviors most often seen were contact-sit, embrace and grooming. The affiliative contacts between adult females occur due to selective attraction, i.e. reconciliation. The pattern of postconflict affiliation demonstrates that the R. roxellana belongs to a tolerant species.
Dominance hierarchy reflects resource competition in male primates as well as females.In this study,we collected data on the social rank and mating competition of female Sichuan snub-nosed monkeys from September 2009 to June 2010 in the Qinling Mountains,Shaanxi,China.Displacement was used to determine social hierarchy of the studied wild females.A total of 1223 displacement bouts between adult females and 316 mating behaviors within one-male units(OMUs) were recorded.Competitive displacement among females was very low(0.22 displacements per observation hour).The dominant ranks of females in target OMUs were determined by displacement,from one OMU to another:JB unit:YL > DBC > YCM >XBC > BD;JZT unit:XHW > JG > DT;PK unit:QQ > TM > HF;LP unit:SK > TH > WM.Higher-ranking females performed significantly more sexual behavior than lower-ranking females in this rare monkey.High-ranking females were more likely to win mating contests within those OMUs.Based on these studies,we assessed the social relationships among adult females and clarified possible explanations for the strategies of female mating competition in the OMUs.Furthermore,the notion that reproductive success may also be related to female dominance hierarchies in this polygynous species should be considered in future research.
HE HaiXiaZHAO HaiTaoQI XiaoGuangWANG XiaoWeiGUO SongTaoJI WeiHongWANG ChengLiangWEI WeiLI BaoGuo
