Doctoral Dissertation Improvement: Endocrine and Behavioral Correlates of Female Social Dominance in Eulemur

雌性对雄性的社会支配（FSD）是大多数马达加斯加狐猴的特征，占所有灵长类动物的近30%；然而，人们对这种不寻常现象的进化或机制知之甚少。与FSD相关的是女性的一系列行为、生理和形态特征，这些特征暗示（作为一种可能的机制）通过暴露于雄激素而“男性化”。鉴于这种联系，杜克大学的博士生Joseph Petty在Christine Drea博士的指导下，采用比较和综合的方法来研究神经内分泌系统，特别是雄激素在调节狐猴FSD中的作用。本项目研究了6种亲缘关系密切的Eulemur物种的混合性别对，这些物种表现出从攻击性的FSD到两性间的共同优势的行为变化梯度，该项目将描述每个物种的两性间优势、隶属关系和攻击性的表达。通过分析血液样本中的类固醇激素雄烯二酮（A4）、睾酮(T)、雌二醇（E2）以及神经递质5-羟色胺（5-HT），将进一步提供与行为相关的神经内分泌方面的新信息。最后，为了提供与FSD相关的行为与神经内分泌网络之间跨物种直接因果联系的证据，将通过实验操纵内分泌系统，使用促性腺激素释放激素拮抗剂（antide），以评估雌性狐猴雄性化行为的行为和社会影响。该项目独特的比较和实验视角将提供对灵长类社会系统中雌性优势进化的更多理解，以及对自然循环激素在调节雌性行为中的直接激活作用的洞察。它的非传统焦点有可能帮助更新当前对性选择的定义，以更好地反映女性性内竞争的重要性，并改变当前对生理和社会优势表达的基本机制的理解。该项目将在北卡罗来纳州达勒姆的杜克狐猴中心进行，在那里它为研究、技术和教育人员提供了合作的机会。通过这些合作，该项目促进了对本科生研究人员的指导，传播了与狐猴生物学和保护有关的信息，进行了公众宣传，并为儿童提供了动手科学经验。

Female social dominance (FSD) over males characterizes most Malagasy lemurs, which represent almost 30% of all primates; yet, little is known about the evolution or mechanism of this unusual phenomenon. Associated with FSD is a suite of behavioral, physiological, and morphological traits in females that implicates (as a possible mechanism) 'masculinization' via androgen exposure. In light of this association, this project by doctoral student Joseph Petty (Duke University), under the guidance of Dr. Christine Drea, takes a comparative and integrative approach to investigating the role of the neuroendocrine system, particularly androgens, in regulating FSD in lemurs. Studying mixed-sex pairs of six closely related Eulemur species that express a gradient of behavioral variation, from aggressive FSD to co-dominance between the sexes, this project will characterize the expression of intersexual dominance, affiliation, and aggression for each species. It will further provide novel information about the neuroendocrine correlates of behavior through the analysis of blood samples for the steroid hormones androstenedione (A4), testosterone (T), and estradiol (E2), as well as the neurotransmitter serotonin (5-HT). Lastly, to provide evidence of a direct causal linkage across species between behavior associated with FSD and neuroendocrine networks, the endocrine system will be experimentally manipulated, using a gonadotrophin-releasing hormone antagonist (antide), to assess the behavioral and social effects on masculinized behavior in female lemurs.This project's unique comparative and experimental perspective will provide an increased understanding of the evolution of female dominance in primate social systems, as well as insight into the direct activational role of naturally circulating hormones in the regulation of female behavior. Its nontraditional focus has the potential to help update current definitions of sexual selection to better reflect the importance of intrasexual competition in females and to transform current understanding of the proximate mechanisms that underlie the physiology and expression of social dominance.This project will be conducted at the Duke Lemur Center in Durham, NC, where it provides opportunities for collaborations with research, technical, and educational staff. Through these collaborations, this project facilitates mentorship of undergraduate researchers, dissemination of information relevant to lemur biology and conservation, public outreach, and hands-on science experience for children.