Garcia Cécile, Shimizu Keiko, Huffman Michael
Laboratoire de dynamique de l'évolution humaine, CNRS UPR 2147, Paris, France.
Am J Primatol. 2009 Oct;71(10):868-79. doi: 10.1002/ajp.20717.
Japanese macaques live in multi-male/multi-female social groups in which competition between males, female mate choice, and alternative male mating strategies are important determinants of mating and reproductive success. However, the extent to which adult males rely on female behavior to make their mating decisions as well as the effect of social rank on mating success are not clear as results are inconclusive, varying from study to study. In this study, we combined behavioral and endocrine data of 14 female Japanese macaques to examine the relationship between ovarian cycle phase and frequency of sexual behaviors, and to investigate how social rank influences sexual behavior in this species. We found that there was no increase in female proceptive behaviors during the fertile phase of the ovarian cycle, suggesting that female behaviors did not clearly signal the probability of conception. In spite of that, the frequencies of ejaculatory copulations were highest during this phase, indicating that the attractivity of females increased significantly during the period with higher probability of conception. Males, and especially the highest ranking male, were able to discriminate females nearing ovulation and to concentrate their mating effort, implying that the timing of ovulation was not concealed from them. The alpha male seemed able to monopolize most female matings, which is probably due in part to the low number of females simultaneously ovulating and to the limited number of inconspicuous places that the lower ranking males have to mate with females and avoid alpha male aggression. All together, these results suggest that different males may have access to different signals of ovulation and/or are differentially restrained as to how they can act on that information. The exact nature of the estrogen-related cues males use to recognize female reproductive status, and to what extent males use them warrants further investigation.
日本猕猴生活在多雄多雌的社会群体中，其中雄性之间的竞争、雌性的配偶选择以及雄性的替代交配策略是交配和繁殖成功的重要决定因素。然而，成年雄性在做出交配决策时依赖雌性行为的程度以及社会等级对交配成功的影响尚不清楚，因为研究结果尚无定论，不同研究之间存在差异。在本研究中，我们结合了14只雌性日本猕猴的行为和内分泌数据，以研究卵巢周期阶段与性行为频率之间的关系，并探讨社会等级如何影响该物种的性行为。我们发现，在卵巢周期的排卵期，雌性的性接受行为并没有增加，这表明雌性行为并没有明确地表明受孕的可能性。尽管如此，射精性交的频率在这个阶段最高，这表明在受孕概率较高的时期，雌性的吸引力显著增加。雄性，尤其是等级最高的雄性，能够辨别接近排卵期的雌性，并集中它们的交配努力，这意味着排卵时间对它们来说并没有被隐藏。优势雄性似乎能够垄断大多数雌性的交配，这可能部分是由于同时排卵的雌性数量较少，以及地位较低的雄性与雌性交配并避免受到优势雄性攻击的隐蔽场所数量有限。总之，这些结果表明，不同的雄性可能获得不同的排卵信号，并且/或者在如何根据这些信息采取行动方面受到不同程度的限制。雄性用来识别雌性生殖状态的与雌激素相关线索的确切性质，以及雄性在多大程度上利用这些线索，还有待进一步研究。
