Jin Tong, Wang De-Zhi, Zhao Qing, Yin Li-Jie, Qin Da-Gong, Ran Wen-Zhong, Pan Wen-Shi
Giant Panda and Wildlife Conservation Research Center, School of Life Sciences, Peking University, Beijing, People's Republic of China.
Am J Primatol. 2009 Mar;71(3):206-13. doi: 10.1002/ajp.20637.
The number of males per group is the most variable aspect of primate social organization and is often related to the monopolizability of females, which is mainly determined by the number of females per group and their reproductive synchrony. Colobines show both inter-specific and intra-specific variations in the number of males per group. Compared with other colobine species, little is known about the social organization of white-headed langur (Trachypithecus leucocephalus), despite its endangered status and unusual limestone habitat. As a part of a long-term study of the white-headed langurs in the Nongguan Karst Hills, Guangxi, China, we quantitatively investigated their social organization by analyzing census data from 1998 to 2003. The population censuses revealed that the predominant social organization of bisexual groups was the one-male group, similar to a previous report on this species and many other Asian colobines. In such groups, one adult male associated with 5.1 adult females, 0.1 sub-adult males, 2.6 juveniles and 2.9 infants on average, with a mean group size of 11.7 individuals. In addition, three multi-male groups were recorded, consisting of 2-3 adult males, 1-5 adult females, 0-2 sub-adult males, 0-7 juveniles and 0-2 infants. They did not contain more adult females than the one-male groups and were unstable in group membership. The langurs outside bisexual groups were organized into small nonreproductive groups or lived as solitaries. The nonreproductive groups averaged 1.3 adult males, 1.3 sub-adult males and 2.6 juveniles. Juvenile females were present in such groups on 52.4% of all occasions. As predicted by the monopolization model, the prevalence of the one-male pattern in this species may mainly be attributed to the small number of females in the group. The possible reasons for the occurrence of multi-male groups and the presence of juvenile females in nonreproductive groups are also discussed.
每组雄性的数量是灵长类社会组织中最具变化性的方面，并且通常与雌性的可独占性相关，而雌性的可独占性主要由每组雌性的数量及其繁殖同步性决定。疣猴亚科在每组雄性数量上表现出种间和种内差异。与其他疣猴亚科物种相比，尽管白头叶猴（Trachypithecus leucocephalus）处于濒危状态且栖息地为特殊的石灰岩环境，但对其社会组织的了解却很少。作为对中国广西弄官喀斯特山区白头叶猴进行长期研究的一部分，我们通过分析1998年至2003年的普查数据，对它们的社会组织进行了定量研究。种群普查显示，两性群体中占主导地位的社会组织是单雄群体，这与之前关于该物种以及许多其他亚洲疣猴的报告相似。在这类群体中，一只成年雄性平均与5.1只成年雌性、0.1只亚成年雄性、2.6只幼猴和2.9只婴猴生活在一起，平均群体规模为11.7只个体。此外，还记录到了三个多雄群体，由2至3只成年雄性、1至5只成年雌性、0至2只亚成年雄性、0至7只幼猴和0至2只婴猴组成。它们的成年雌性数量并不比单雄群体多，并且群体成员不稳定。两性群体之外的叶猴组成小型非繁殖群体或独居生活。非繁殖群体平均有1.3只成年雄性、1.3只亚成年雄性和2.6只幼猴。在所有观察场合中，有52.4%的情况下这类群体中有未成年雌性。正如独占模型所预测的，该物种中单雄模式的普遍存在可能主要归因于群体中雌性数量较少。文中还讨论了多雄群体出现以及未成年雌性存在于非繁殖群体中的可能原因。
