DISSERTATION RESEARCH: Androgen regulation of territorial male-typical behavior and neuropeptide gene expression during socially-induced sex and role change in a coral reef fish

论文研究：珊瑚礁鱼在社会诱导的性别和角色变化过程中雄激素对领地雄性典型行为和神经肽基因表达的调节

• 批准号: 1406863
• 负责人: John Godwin
• 金额: $ 1.88万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1406863&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Androgen; regulation; territorial

The ability to respond and adapt to current environmental or social condition, depends to a large extent of the flexibility to make behavioral, physiological and neurological changes. An area of great interest is the plasticity of the brain to change in response to new challenges. One of the greatest examples of this ability is seen in fish that are capable of switching from female-to-male or male-to-female either behavioral or phenotypically. This occurs when changes in the population, loss of males or females increase the ability to reproduce by changing. In species with socially-controlled sex change and/or role change, the brain perceives alterations in the social environment that indicate it is favorable for these changes and therefore "permissive". This is observed in the bluehead wrasse (Thalassoma bifasciatum), a Caribbean coral reef fish with a lek-like mating system in which territorial-terminal phase (T-TP) males defend spawning territories for access to females and breed with multiple females. Removal of a T-TP male from a spawning territory creates a permissive environment that induces sex change in the largest female or male role change in the largest non-territorial male, either an initial phase (IP) male or non-territorial-terminal phase (NT-TP) male. This research will examine the role androgen hormones in response to changing social influences to promote behavioral and phenotypic changes. These types of studies are important as they have the ability to demonstrate the constraint of social interactions and the brains ability to change to when constraints are left or there are major changes in the environment. Within minutes-to-hours of removing a bluehead wrasse T-TP male from its territory, changes in the brain of the largest female, IP male, or NT-TP male induce T-TP male-typical behaviors, such as courtship of females and agonistic behavior directed at other males. Changes in the brain also activate the hypothalamo-pituitary-gonadal (HPG) axis, causing transformation of female ovaries or IP male testes into TP male testes. Androgen production, particularly of 11KT, rises during gonadal transformation in both females and subordinate males during sex and role change. While previous studies show 11KT increases are not necessary for behavioral changes, other observations nevertheless suggest this androgen may play an important role. The neuropeptide vasotocin (homologue of vasopressin in mammals) appears responsible for early behavioral changes. However, could the presence of 11KT induce earlier onset of behavioral changes and increase the display of T-TP male-typical behaviors? NT-TP males have higher baseline levels of 11KT than IP males and females and appear to transition into the role of T-TP male faster. Is 11KT responsible for faster role change? The researchers hypothesize that 11KT promotes behaviors and gene expression profiles typical of T-TP phase males under permissive social conditions. Using a combination of capture/tag-and-release/recapture approaches, hormonal manipulations via gonadectomy and 11KT implantation, behavioral observations of tagged individuals, 11KT serum assays, and gene expression analysis via qRT-PCR, this study will test whether 1) significant differences exist in the timing, frequency, and duration of T-TP male-typical behaviors among females, IP males, and NT-TP males undergoing sex and role change under permissive conditions, 2) gonadal presence affects T-TP male-typical behaviors and gene expression of the vasotocin system and two other neuropeptide systems, kisspeptin and gonadotropin-releasing hormone, during sex and role change, and 3) 11KT promotes T-TP male-typical behaviors and gene expression of these neuropeptide systems during sex and role change. This study will help determine whether 11KT confers an advantage for individuals competing to become the territorial phenotype

对当前环境或社会条件的反应和适应能力在很大程度上取决于做出行为，生理和神经变化的灵活性。 一个非常有趣的领域是大脑的可塑性，以应对新的挑战。这种能力的一个最好的例子是在鱼类中看到的，它们能够从雌性转换为雄性或从雄性转换为雌性，无论是行为上还是表型上。当种群发生变化时，雄性或雌性的损失会通过改变来增加繁殖能力。在具有社会控制的性别变化和/或角色变化的物种中，大脑感知到社会环境的变化，这表明它有利于这些变化，因此是“允许的”。这是观察到的蓝头濑鱼（Thalassoma bifasciatum），加勒比珊瑚礁鱼与lek一样的交配系统，其中领土终端阶段（T-TP）男性捍卫产卵领土访问女性和多个女性繁殖。从产卵领域的T-TP男性的删除创建一个宽松的环境，诱导性别变化的最大的女性或男性角色的变化，在最大的非领土男性，无论是初始阶段（IP）男性或非领土终端阶段（NT-TP）男性。这项研究将探讨雄激素在应对不断变化的社会影响，促进行为和表型变化的作用。这些类型的研究很重要，因为它们能够证明社会互动的约束以及大脑在约束消失或环境发生重大变化时的变化能力。 在几分钟到几小时内，从其领土上删除蓝头濑鱼T-TP男性，最大的女性，IP男性，或NT-TP男性的大脑的变化诱导T-TP男性典型的行为，如求爱的女性和竞争行为针对其他男性。大脑的变化也激活了下丘脑-垂体-性腺（HPG）轴，导致雌性卵巢或IP雄性睾丸转化为TP雄性睾丸。雄激素的生产，特别是11 KT，上升在性腺的转换过程中，女性和下属男性在性别和角色的变化。虽然以前的研究表明，11 KT增加不是行为改变所必需的，但其他观察结果表明，这种雄激素可能起着重要作用。神经肽血管催产素（哺乳动物中加压素的同系物）似乎与早期行为变化有关。然而，11 KT的存在是否可以诱导行为改变的早期发生，并增加T-TP男性典型行为的显示？NT-TP男性的11 KT基线水平高于IP男性和女性，并且似乎更快地过渡到T-TP男性的角色。11 KT负责更快的角色转变吗？研究人员假设，11 KT促进了T-TP期男性在宽松的社会条件下的典型行为和基因表达谱。使用捕获/标记-和-释放/再捕获方法、通过性腺切除术和11 KT植入的激素操作、标记个体的行为观察、11 KT血清测定和通过qRT-PCR的基因表达分析的组合，本研究将测试1）在雌性、IP雄性、和在允许条件下经历性别和角色改变的NT-TP男性，2）在性别和角色改变期间，性腺的存在影响T-TP男性典型行为和催产素系统和两个其他神经肽系统（kisspeptin和促性腺激素释放激素）的基因表达，3）11 KT促进T-TP雄性化行为和这些神经肽系统在性别和角色转换中的基因表达。这项研究将有助于确定11 KT是否赋予竞争成为领土表型的个体优势