DISSERTATION RESEARCH: Hormonal Regulation of Avian Biparental Care

亲代抚育是繁殖的一个重要组成部分，在各种动物中都可以观察到，在鸟类中尤其常见。鸟类亲代抚育的神经和激素基础尚不清楚，特别是在许多由父母共同抚养幼鸟的鸟类中。在哺乳动物中，催乳素在母系抚育中扮演着重要的角色，因此，催乳素及其脑受体是研究鸟类亲代抚育的一个有希望的候选机制。本研究的目的是通过实验测试催乳素在促进双亲鸣禽（斑胸草雀）亲代行为发生中的因果作用。这项研究将为鸟类亲代抚育的机制提供新的见解，允许将这一重要群体整合到比较框架中，这将为理解这些机制如何在其他动物（包括人类）中发挥作用和进化提供预测能力。该项目将有助于大学生，包括妇女和代表性不足的少数民族的科学培训。此外，研究结果将迅速发表在广大研究人员可以访问的期刊上，在全国会议上发表，并通过网站和面向中学女生的推广项目向公众传播。研究人员确定，与繁殖周期中的其他时间相比，斑胸草雀（Taeniopygia guttata）在孵化后期和孵化后早期护理期间的循环催乳素（PRL）明显更高。为了验证PRL在促进亲代行为发生中起因果作用的假设，他们将进行两个实验，测试在育雏鸟的孵化后期抑制PRL的正常峰值的效果，以及实验增加配对但非育雏鸟的PRL。父母的行为将在巢中用小型摄像机记录下来。为了确认治疗对PRL浓度有预期的影响，将在治疗前后使用经验证的ELISA检测血浆。在治疗的最后一天，将收集大脑，利用免疫组织化学方法确定通过PRL受体对中枢PRL介导的细胞信号传导的影响。所有数字形式的录音和数据将在康奈尔大学存档，允许公众使用科罗拉多大学图书馆的存档服务访问。

Parental care is an important component of reproduction that is observed in a diverse range of animals and is especially common in birds. The neural and hormonal basis of avian parental care is not well understood, especially in the many birds where young are raised by both mothers and fathers working together. The hormone prolactin has a well-established role in maternal care in mammals, and so prolactin and its brain receptors are a promising candidate mechanism of parental care to investigate in birds. The goal of this research is to experimentally test for a causal role of prolactin in promoting the onset of parental behavior in a biparental songbird, the zebra finch. This research will provide new insight into the mechanisms of avian parental care, allowing the integration of this important group into the comparative framework that will provide the predictive power for understanding how these mechanisms may function and evolve in other animals, including humans. The project will contribute to the scientific training of undergraduates, including women and underrepresented minorities. Additionally, the results will be promptly published in journals accessed by a broad audience of researchers, presented at national meetings, and disseminated to the public through a website and outreach programs for middle school girls. The researchers determined that circulating prolactin (PRL) is significantly higher in zebra finches (Taeniopygia guttata) during late incubation and early post-hatching care compared to other times in the breeding cycle. To test the hypothesis that PRL plays a causal role in promoting the onset of parental behavior, they will perform two experiments testing the effect of suppressing the normal peak in PRL during late stage incubation in breeding birds, and experimentally increasing PRL in paired, but non-breeding, birds given foster chicks. Parental behavior will be recorded in the nests with small video cameras. To confirm that the treatments have the predicted effect on PRL concentrations, plasma will be assayed before and after treatment using a validated ELISA. On the last day of treatment brains will be collected to determine the effect on central PRL-mediated cell signaling via the PRL receptor using immunohistochemistry. All recordings and data in digital form will be archived at Cornell University to allow public access using the archiving services of the CU Library.