Doctoral Dissertation Improvement Grant: Effects of Hormonal and Social Factors on Primate Behavior

在Leanne Nash博士的指导下，Stephanie Meredith女士将为她的博士论文收集数据。大量研究表明，灵长类动物行为中性别差异的发展取决于个体外部社会环境与其内部生理状态（特别是由下丘脑-垂体-性腺轴控制的激素）之间复杂的相互作用。然而，对社会环境的特定方面和个体生理的特定组成部分对特定性别类型行为发展的相对重要性的理解是模糊的。这对于在幼年时期开始性别分化的行为来说尤其如此。此外，由于这一领域的几乎所有研究都是在圈养动物身上进行的，因此尤其不清楚社会和生理因素如何在自然环境中相互作用，从而形成行为结果。因此，人们对产生适应性行为性别差异的社会和生理系统的进化知之甚少。本项目将研究马达加斯加贝扎马哈法利特别保护区的环尾狐猴（Lemur catta）野生种群从出生到性成熟期间的社会交往和类固醇激素睾酮和雌二醇对性别型社会发展的影响。环尾狐猴是研究灵长类动物性别型行为发展的社会和生理影响的一个引人注目的模型系统，因为尽管它们在社会组织的许多方面与研究得更好的圈养猴子相似，但它们在表现出雌性对雄性的统治方面与大多数其他灵长类动物截然不同。这种相似性和差异性的结合将最大限度地提高对“先天”、“后天”及其相互作用对大量行为特征发展的相对重要性进行分类的能力，并将指出富有成效的未来研究方向。这个项目将是第一个为培育狐猴猫产生生理数据的项目。对于本研究中特定的环尾狐猴，这项工作将有助于解释它们的发育生物学和最终的终身繁殖成功。这些数据，加上来自圈养环境的数据，将有助于将圈养环境下的发育研究结果置于背景中。此外，当与其他灵长类动物的类似数据进行比较时，这些数据将有助于查明灵长类动物复杂的性别类型行为的生物学和社会基础，并最终阐明灵长类动物性别类型行为的进化。除了对科学知识的贡献之外，该项目还将培训发展中国家的科学家，并将为女性博士候选人扩展技能集和增加可用的研究途径。这一奖项也具有重大的保护意义，无论是现在还是未来。该奖项的结果将为贝扎马哈法利特别保护区的管理和评估栖息地退化对其他地方的幼年狐猴的影响提供有用的行为和激素基准。由于科学研究是贝扎马哈法利特别保护区保护其濒危动物的重要和稳定的经济力量，因此提高马达加斯加未来研究的潜力是一个重要的积极影响。

Under the direction of Dr. Leanne Nash, Ms. Stephanie Meredith will collect data for her doctoral dissertation. A great deal of research has demonstrated that the development of sex differences in primate behavior depends on complex interactions between individual's external social environments and their internal physiological states (particularly the hormones governed by the hypothalamic-pituitary-gonadal axis). However, understanding of the relative importance of particular aspects of the social environment and specific components of individual physiology for the development of particular sex-typed behaviors is murky. This is especially true for behaviors which begin their sexual differentiation in the juvenile period. Furthermore, because almost all research in this area has been done on captive animals, it is especially unclear how social and physiological factors interact in natural environments to shape behavioral outcomes. As a result, very little is known about the evolution of social and physiological systems that produce adaptive sex-differences in behavior. This project will investigate the influence of social interaction and the steroid hormones testosterone and estradiol on sex-typed social development from birth through sexual maturity in a wild population of ring-tailed lemurs (Lemur catta) at Beza Mahafaly Special Reserve in Madagascar. Ring-tailed lemurs represent a compelling model system for study of social and physiological influences on primate sex-typed behavioral development because while they are similar to the better-studied captive monkeys in many aspects of social organization, they are strikingly different from most other primates in exhibiting female dominance over males. This combination of similarities and differences will maximize the ability to sort out the relative importance of "nature," "nurture," and their interaction for the development of a large number of behavioral traits and will indicate productive future research directions. This project will be the first to generate physiological data for developing Lemur catt. For the particular ring-tailed lemurs in this study, this work will be useful in interpreting their developmental biology and eventual lifetime reproductive success. These data, coupled with those derived from captive settings, will help to contextualize the results of developmental research in captivity. In addition, when compared to similar data from other primates, these data will help to pinpoint the biological and social underpinnings of complex, sex-typed behaviors across the primate order, and, ultimately, to clarify the evolution of primate sex-typed behavior.Beyond its contributions to scientific knowledge, this project will train developing scientists and will expand the skill set of and increase available research avenues for a female Ph.D candidate. This award also has major conservation implications, both present and future. Results from this award will provide behavioral and hormonal benchmarks useful for Beza Mahafaly Special Reserve management and for assessing the impact of habitat degradation on juvenile Lemur catta elsewhere. Because scientific research is a substantial and stabilizing economic force at Beza Mahafaly Special Reserve in protecting its endangered fauna, enhancing the potential for future research in Madagascar is an important positive impact.