Supplementary Material for: Allogrooming in Male-Female Pairs of Captive Owl Monkeys (Aotus nancymaae)

Owl monkeys (Aotus spp.) are socially monogamous, yet allogrooming is reported to be rare. Because Aotus are nocturnal and arboreal, allogrooming is difficult to observe in natural settings. We observed 21 male-female pairs of captive Aotus nancymaae during 2 nonconsecutive study periods in order to describe the details of allogrooming between mates (partner grooming). We found that grooming bouts are brief and consist of tugging the hair or skin with flexed fingers and/or the mouth. Males groomed females most often, and their rates of partner grooming were negatively related to age. Partner grooming occurred regardless of mating behavior. Camera trap data revealed that the rate of partner grooming (1.50 bouts/h) is greater than that recorded from our direct observations in the early evenings (0.51 bouts/h, in 2013; 0.37 bouts/h in 2003) given that most bouts occurred later in the night. A positive relationship between the rates of the parents' partner grooming and those of their offspring later in life suggests intergenerational transmission. This relationship is influenced by the fathers' rates of partner grooming. We conclude that allogrooming in Aotus is a normal part of their behavioral repertoire that likely serves social functions similar to those in other pair-bonded primates.

夜猴（Aotus spp.）为社会单配制物种，但据报道其异体理毛（allogrooming）行为较为罕见。由于夜猴属于夜行性树栖动物，野外自然环境下的异体理毛行为难以被直接观测。本研究在两个非连续的研究周期内，观测了21对圈养的纳氏夜猴（Aotus nancymaae）雌雄配对个体，旨在描述配偶间异体理毛（即伴侣理毛，partner grooming）的具体细节。研究发现，单次理毛回合时长较为短暂，行为模式为以屈曲的手指或/和口腔牵拉毛发与皮肤。其中雄性对雌性的理毛行为最为频繁，且雄性的伴侣理毛频率与其年龄呈负相关。伴侣理毛行为的发生与交配行为并无关联。红外相机监测数据显示，伴侣理毛频率可达1.50次/小时，高于本研究早期晚间的直接观测结果（2013年为0.51次/小时，2003年为0.37次/小时），这是由于绝大多数理毛事件均发生在夜间较晚时段。双亲的伴侣理毛频率与其后代成年后的理毛频率呈正相关，提示该行为存在代际传递现象，且该相关关系受父亲的伴侣理毛频率影响。综上，本研究认为夜猴的异体理毛是其行为谱中的正常组成部分，其社会功能大概率与其他实行配偶结合的灵长类动物相似。