Group size and reproductive success of female and male blue monkeys

社会性是灵长类秩序的一个标志，而理解群体生活的选择性优势已被证明是一个持久的问题。研究人员正在研究肯尼亚卡卡梅加热带雨林中六组不同大小五倍的野生蓝猴，以了解群体生活的进化基础。这个项目的重点是群体规模的变化如何影响野生雌性和雄性蓝猴的生物适合度。团体规模预计将反映团体生活对个别团体成员的成本和收益。雌性在食物获取方面与群体成员展开激烈的竞争，当群体变得庞大时，雌性群体就会分裂。这样的观察表明，生活在更大的群体中是有代价的，而主要由雌性进行的集体领土和捕食者防御也表明了好处。研究小组调查了群体规模如何影响女性的健康，直接通过出生间隔、婴儿存活和第一个孩子的年龄来衡量，并通过喂养和社会行为方面间接衡量。这一物种的雄性试图垄断雌性群体，在更大的群体中应该有更多的生殖机会。然而，男性生殖分区的模型表明了其他重要因素，如女性生殖同步性、入侵者压力和男性自身的生殖史。这个项目阐明了哪些因素最好地解释了雄性生殖的巨大差异。研究人员监测人口统计变化、女性社会和性行为，并使用微卫星座位收集粪便样本进行遗传亲子鉴定。研究人群是为数不多的存在长期人口数据的人群之一。该项目直接测量与社会和生态驱动相关的生殖结果。该项目支持一名女研究生的论文研究，以及其他本科生、硕士和博士生的研究培训。与一所新成立的肯尼亚大学开展的国际合作促成了与实地地点有关的森林生态方面的专门知识；项目人员为一个基层社区保护组织提供支持，并为正在制定Kakamega森林参与式管理计划的科学小组提供咨询。

Sociality is a hallmark of the primate order, and understanding the selective advantage of group living has proved an enduring question. The researchers are studying six groups of wild blue monkeys (Cercopithecus mitas stuhlmanni), differing five-fold in size, in the Kakamega, Kenya rain forest to understand the evolutionary basis of group living. This project focuses on how variation in group size influences biological fitness in of wild female and male blue monkeys. Group size is expected to reflect costs and benefits of group living to individual group members. Females compete aggressively with group-mates over access to food, and engineer group splits when groups become large. Such observations suggest costs to living in larger groups, while collective territorial and predator defense, mainly by females, also suggests benefits. The research team investigates how group size influences female fitness, measured directly in terms of inter-birth interval, infant survival, and age at first birth, and indirectly by aspects of feeding and social behavior. Males of this species try to monopolize groups of females, and should have more reproductive opportunities in larger groups. Models of male reproductive partitioning suggest additional important factors, however, like female reproductive synchrony, intruder pressure and a male's own reproductive history. This project clarifies which factors best explain the considerable variation in reproduction among males. The researchers monitor demographic changes, female social and sexual behavior, and collect fecal samples for genetic paternity assignment using microsatellite loci. The study population is one of very few in which long-term demographic data exist. This project directly measures reproductive outcomes as related to social and ecological drivers.This project supports the dissertation research of a female graduate student, and research training of other undergraduate, M.A., and Ph.D. students. International collaboration with a new Kenyan university has led to building expertise in forest ecology related to the field site; the project personnel support a grass-roots community-based conservation organization, and advise the scientific team that is developing the participatory management plan for the Kakamega Forest.