title: Evidence of male-biased dispersal in the endangered Sichuan snub-nosed monkey (Rhinopithexus roxellana).
abstract: Although sex-biased dispersal has profound effects on the viability of small and isolated populations resulting from habitat change and anthropogenic disturbance, the direction and strength of sex-biased dispersal in the endangered Sichuan snub-nosed monkey (Rhinopithexus roxellana) remains poorly understood. Here, we investigated dispersal patterns of R. roxellana using 15 polymorphic microsatellite loci. Using noninvasive methods we obtained 337 fecal samples from individuals residing in four multilevel troops that inhabit the Shennongjia Nature Reserve (SNR). Our study site contains an isolated population of approximately 1,000 Sichuan snub-nosed monkeys located in the easternmost distribution of the species' range. Our results indicated that the mean coefficient of relatedness among troop members was low (mean relatedness ± SE = 0.038 ± 0.025). However, the mean relatedness of monkeys residing in the same troop was significantly higher than the mean relatedness of monkeys belonging to different troops, suggesting that some members of the same troop were closely relatived. Sex-biased dispersal tests revealed that dispersal in R. roxellana was male-biased. Moreover, analysis of isolation-by-distance indicated that the correlation between pairwise genetic distance and geographical distance was positive for females, while it was negative for males. These data suggest that males tended to disperse further than females, although these values were not statistically significant. Considering previous field data collected on Sichuan snub-nosed monkeys from other sites, we suggest that mating competition among males and female mate choice represent the major causes of male-biased dispersal in R. roxellana.
authors.affiliation: Key Lab of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; Graduate School of the Chinese Academy of Sciences, Beijing, China.
authors.forename: Zongfei
authors.initials: Z
authors.lastname: Chang
authors.forename: Banghe
authors.initials: B
authors.lastname: Yang
authors.forename: Linda
authors.initials: L
authors.lastname: Vigilant
authors.forename: Zhijin
authors.initials: Z
authors.lastname: Liu
authors.forename: Baoping
authors.initials: B
authors.lastname: Ren
authors.forename: Jingyuan
authors.initials: J
authors.lastname: Yang
authors.forename: Zuofu
authors.initials: Z
authors.lastname: Xiang
authors.forename: Paul A
authors.initials: PA
authors.lastname: Garber
authors.forename: Ming
authors.initials: M
authors.lastname: Li
mesh_terms: D063147:Animal Distribution; D000818:Animals; D002681:China; D016673:Colobinae / Q000235:genetics / Q000502:physiology*; D003163:Competitive Behavior; D056727:Endangered Species; D005260:Female; D051456:Gene Flow; D008297:Male
keywords: Rhinopithecus roxellana; dispersal; genetic structure; relatedness