Korstjens Amanda H, Noë Ronald
Behavioral Biology Department, Utrecht University, Utrecht, The Netherlands.
Am J Primatol. 2004 Apr;62(4):261-73. doi: 10.1002/ajp.20020.
In the olive colobus (Procolobus verus), many groups have multiple males and the males have large testes. This indicates that even though this species lives in small groups, single males do not monopolize the groups. We investigated the strategies employed by males to secure their mating success, and sought to determine whether the lack of male monopolization was a result of female mating strategies, as indicated by the exaggerated sexual swellings of the females. Four study groups were monitored for demographic changes, and group composition was determined in six additional groups in Taï National Park, Ivory Coast, between 1994 and 1999. Social behavior was recorded by scan and focal sampling in the study groups. The almost permanent association of olive colobus with Diana monkeys (Cercopithecus diana) in effect provided males a resource at which they could expect females to visit and sometimes even permanently join them, as well as protection from predators. As alternative strategies for obtaining females, one male took over the group of another male and one male immigrated into a bisexual group. Within bi-male groups, dominant males mated most frequently and males defended their groups during intergroup interactions. Lone females that visited groups or solitary males had a swelling more often than expected, and generally mated with the males they visited. Females had long receptive periods, several consecutive receptive cycles, and some overlap in receptive periods within groups. Females mated with extragroup males, and during infertile periods. We concluded that the males used the Diana monkeys for safety reasons and to obtain mating partners, and that female reproductive biology and behavior prevented the monopolization of groups of females by single males. Our data were inconclusive as regards the benefits to females of avoiding monopolization by males.
在橄榄疣猴（Procolobus verus）中，许多群体有多个雄性，且雄性有较大的睾丸。这表明尽管该物种生活在小群体中，但单个雄性并不会独占群体。我们研究了雄性为确保交配成功所采用的策略，并试图确定缺乏雄性独占是否是雌性交配策略的结果，正如雌性夸张的性肿胀所表明的那样。1994年至1999年间，对四个研究群体进行了人口统计学变化监测，并在科特迪瓦伊塔伊国家公园的另外六个群体中确定了群体组成。通过扫描和焦点取样记录研究群体中的社会行为。橄榄疣猴与戴安娜猴（Cercopithecus diana）几乎永久的关联实际上为雄性提供了一种资源，它们可以期待雌性前来拜访，有时雌性甚至会永久加入它们，同时还能免受捕食者的侵害。作为获取雌性的替代策略，一只雄性接管了另一只雄性的群体，还有一只雄性迁入了一个两性群体。在双雄性群体中，占主导地位的雄性交配最为频繁，并且在群体间互动时雄性会保卫自己的群体。拜访群体的独居雌性或独居雄性出现肿胀的频率高于预期，并且通常会与它们拜访的雄性交配。雌性有较长的接受期、几个连续的接受周期，并且群体内接受期存在一些重叠。雌性会与群体外的雄性交配，并且在非繁殖期也会交配。我们得出结论，雄性出于安全原因并为了获取交配伙伴而利用戴安娜猴，并且雌性的生殖生物学和行为阻止了单个雄性对雌性群体的独占。关于雌性避免被雄性独占的益处，我们的数据尚无定论。
