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
Inter-group conflicts are common among many group-living animals and involve potentially complex motivations and interactions.Mammals living in multilevel societies offer a good opportunity to study inter-group conflicts.This study is the first to explore the function of sex-specific participation during inter-group conflicts within a multilevel society at the individual level.The Sichuan snub-nosed monkey(Rhinopithecus roxellana)is an endangered seasonal breeding species living in a multilevel society.From Sep 2007 to May 2008 we recorded 290 inter-group conflicts of a free-ranging provisioned band of R.roxellana in the Qinling Mountains of China to investigate the function of individual aggression during inter-group encounters.Our findings show that adult males were the main participants in inter-group conflicts,while females took part in them only occasionally.The male participation rate during the mating season,when adult females were estrous,was significantly higher than that during the non-mating season.Furthermore,males directed their aggression to other males,and directed more intense aggression towards bachelor males than towards other resident males.For both sexes,the participation rate as initiators was higher in the winter than that in the spring;and there was a significant positive correlation between group size and the participation rate as initiators.Our results suggest that inter-group aggression in Sichuan snub-nosed monkeys is linked to both mate defense and resource defense.
Genetic variation is generally believed to be important in studying endangered species' adaptive potential.Early studies assessed genetic diversity using nearly neutral markers,such as microsatellite loci and mitochondrial DNA(mtDNA),which are very informative for phylogenetic and phylogeographic reconstructions.However,the variation at these loci cannot provide direct information on selective processes involving the interaction of individuals with their environment,or on the capability to resist continuously evolving pathogens and parasites.The importance of genetic diversity at informative adaptive markers,such as major histocompatibility complex(MHC) genes,is increasingly being realized,especially in endangered,isolated species.Small population size and isolation make the golden snub-nosed monkey(Rhinopithecus roxellana) particularly susceptible to genetic variation losses through inbreeding and restricted gene flow.In this study,we compared the genetic variation and population structure of microsatellites,mtDNA,and the most relevant adaptive region of the MHC II-DRB genes in the golden snub-nosed monkey.We examined three Chinese R.roxellana populations and found the same variation patterns in all gene regions,with the population from Shennongjia population,Hubei Province,showing the lowest polymorphism among three populations.Genetic drift that outweighed balancing selection and the founder effect in these populations may explain the similar genetic variation pattern found in these neutral and adaptive genes.
