Durgavich Lara S, Harwell Faye S, Knott Cheryl D
Anthropology Department, Boston University, Boston, Massachusetts, USA.
Biology Department, Boston University, Boston, Massachusetts, USA.
Am J Primatol. 2023 Mar;85(3):e23420. doi: 10.1002/ajp.23420. Epub 2022 Jul 20.
Knowledge of species-typical reproductive endocrinology profiles is crucial for testing hypotheses pertaining to the evolutionary history, reproductive parameters, and life history of a species, and for managing the well-being of individual animals in human care. Large-scale empirical measurements of ovarian hormones, however, are rare for most primate species, including orangutans. In this study, we used enzyme immunoassays (EIA) to quantify estrogen (estrone conjugates; E C) and progesterone (pregnanediol-3-glucuronide; PdG) levels for 98 cycles in 7 cycling zoo-housed female orangutans (10-43 years old). We use a subset of these cycles (N = 44) to create the first composite menstrual cycle for orangutans, which serves as a valuable baseline for future comparative analyses and veterinary considerations. Similar to previous studies, we determined the mean ovarian cycle length of orangutans to be 29.7 days (N = 98 cycles), although we illustrate evidence of both intra- and interindividual variation in ovarian steroid production. Given that this study took place in captivity, we consider how energetic and psychosocial aspects of the zoo environment, such as greater food availability and potential stress, may affect the reproductive physiology and sexual behavior of these females. Furthermore, we discuss the role that age and genetic background may play in producing variability. Finally, we test whether ovarian hormone levels correlate with the reproductive behaviors of these female orangutans using associated behavioral data. Our results suggest that matings are more common during the periovulatory period than outside of it, but do not support a consistent link between hormonal indices of fecundability and mating behaviors in these individuals.
了解物种典型的生殖内分泌特征对于检验有关物种进化史、生殖参数和生活史的假设，以及管理人工饲养动物个体的健康状况至关重要。然而，对于包括猩猩在内的大多数灵长类物种来说，卵巢激素的大规模实证测量却很少见。在本研究中，我们使用酶免疫分析法（EIA）对7只圈养在动物园的处于发情期的雌性猩猩（10 - 43岁）的98个周期中的雌激素（雌酮结合物；E C）和孕酮（孕二醇 - 3 - 葡糖苷酸；PdG）水平进行了量化。我们利用这些周期中的一个子集（N = 44）创建了首个猩猩的综合月经周期，这为未来的比较分析和兽医考量提供了宝贵的基线。与之前的研究类似，我们确定猩猩的平均卵巢周期长度为29.7天（N = 98个周期），不过我们展示了卵巢类固醇产生的个体内和个体间变异的证据。鉴于本研究是在圈养环境中进行的，我们考虑动物园环境中的能量和心理社会因素，如更充足的食物供应和潜在压力，可能如何影响这些雌性的生殖生理和性行为。此外，我们讨论了年龄和遗传背景在产生变异性方面可能发挥的作用。最后，我们使用相关行为数据测试卵巢激素水平是否与这些雌性猩猩的生殖行为相关。我们的结果表明，排卵期前后的交配比其他时期更为常见，但并不支持这些个体的生育能力激素指标与交配行为之间存在一致的联系。
