Research On Reproductive Competition And Limb Laterality Of Sichuan Snub-nosed Monkeys (Rhinopithecus Roxellana) In The Qinling Mountains

Part OneReproductive Competition of Sichuan Snub-nosed Monkeys (Rhinopithecus roxellana) in the Qinling Mountains,ChinaChapter 1:Impact of male takeover on intra-unit sexual interactions and subsequent inter-birth interval in Rhinopithecus roxellanaData were collected on sexual interactions before and after a male takeover of a one male unit(OMU) of Sichuan snub-nosed monkeys(Rhinopithecus roxellana) at the Zhouzhi National Nature Reserve in the Qinling Mountains of China.The original unit consisted of an adult male,two adult and two subadult females,two female juveniles and a single infant.Following the takeover,the new resident male copulated with one adult female, which was not lactating.Subsequent to the disappearance of her infant,the second(lactating) female entered breeding condition and began to solicit copulation with the new resident male. Subadult females also engaged in matings with the new male.The new resident male was observed mating,on three occasions,with females in two other OMUs.These are the first observations of sexual behavior in free-ranging Sichuan snub-nosed monkeys after an OMU takeover.Sexual interactions play an important role in establishing relationships between the new male and resident females in the OMU. Chapter 2:Mate competition and reproductive correlates of female dispersal in Rhinopithecus roxellanaDifferent mating systems in group-living animals have characteristic behavioral correlates that are primarily related to mate competition.Mate competition may push individuals to selectively make dispersal decisions for the purpose of maximizing of opportunities for reproduction.The Sichuan snub-nosed monkey(Rhinopithecus roxellana) is a polygynous primate species endemic to China.We provide the first data on female dispersal in a free-ranging group of R.roxellana at the Zhouzhi National Nature Reserve in the Qinling Mountains of China.Both adult and subadult female dispersal occurred. Immigration/emigration rates of adult females are higher than those of subadult females.Mate competition is one apparent driving force behind adult female dispersal,and inbreeding avoidance is the possible proximate factor influencing subadult female dispersal.Adult female R.roxellana employ various reproductive strategies related to dispersal,which may increase their reproductive success.Chapter 3:Effect of group size and composition on female reproductive success in Rhinopithecus roxellanaAnimal sociality evolves when gregarious benefits exceed those costs.Group size and group composition,as two basic dimensions of animal sociality,has various effects on the morphological and behavioral variables of group-living animals,such as individual reproductive success.This is the first study on the effect of group size and group composition on female reproductive success in the Rhinopithecus spp.From 2001 to 2008,our data was collected for a flee-ranging group of R.roxellana at the Zhouzhi National Nature Reserve in the Qinling Mountains of China.Female reproductive success of R.roxellana has a significantly linear correlation with both the mean size of each size group and the number of adult females.It suggests that the R.roxellana accords with the basic assumptions of the van Schaik(1983)'s predation-intragroup feeding competition hypothesis.This result raises the possibility that the within-group scramble competition works on female reproductive success in R.roxellana. Part TwoLimb Laterality of Sichuan Snub-nosed Monkeys (Rhinopithecus roxellana) in the Qinling Mountains,ChinaChapter 4:Hand preference during unimanual and bimanual reaching actions in Rhinopithecus roxellanaHand preferences were investigated during one unimanual action(food-reaching) and one bimanual action(mount-reaching) in a free-ranging group of Sichuan snub-nosed monkeys(Rhinopithecus roxellana) at the Zhouzhi National Nature Reserve in the Qinling Mountains of China.Nine of fourteen individuals tested on the unimanual food-reaching action and all six individuals tested on the bimanual mount-reaching action exhibited a manual preference.Both significant right- and left-handed preferences were observed in the two actions.Sex did not affect either direction or strength of hand preference in the unimanual action.Hand preference for the bimanual action was stable over time,and the strength of hand preference was significantly stronger in the bimanual action than in the unimanual action.Chapter 5:Foot Preference during quadrupedal and bipedal actions in Rhinopithecus roxellanaFoot preferences were investigated during the quadrupedal walking action and the bipedal shifting action for a free-ranging group of Sichuan snub-nosed monkeys (Rhinopithecus roxellana) at the Zhouzhi National Nature Reserve in the Qinling Mountains of China.Twelve of 21 individuals tested on the quadrupedal action and all 21 individuals tested on the bipedal action exhibited a significant foot preference.Both significant right- and left-footed preferences were observed and sex did not affect either direction or strength of foot preference in both actions.The finding that 61.90%of focal R.roxellana showed the right-foot preference both in quadrupedal action based on the footed index and in bipedal action based on the z-score are in partial agreement with the postural origin hypothesis on footedness.The strength of foot preference was significantly stronger in the bipedal action than in the quadrupedal action,supporting the view that posture could be a crucial factor influencing foot preference as well as hand preference in this species.Chapter 6:Neonate nipple preference and maternal cradling laterality in Rhinopithecus roxellanaThis study of Sichuan snub-nosed monkeys(Rhinopithecus roxellana) constitutes the first report on asymmetric patterns of early mother-infant interactions among Old World monkeys in the wild.It was found that neonate nipple preference and maternal cradling laterality are both evident on the individual level.Although there is no significant group-level preference direction,the group preference strength on both measures is evident.Moreover, neonate nipple preference is not significantly correlated with maternal cradling laterality on either LBI scores or the direction.Taken together,it is possible to suggest that wild R. roxellana showy independent orientation laterality from the first week of life.