DISSERTATION RESEARCH: Integrating Costs of Investment in Parental Care from Telomeres to Hormones

动物可以通过有许多存活和繁殖的后代而受益。为了增加后代的存活率，父母可能会提供广泛的父母照顾，并表现出对捕食者或入侵者的攻击性。然而，抚养和保护一个大家庭可能会增加父母的压力。此外，激素通常调节行为的表达。例如，睾丸激素与许多鸟类的父母照顾减少和攻击性增加有关。高水平的睾丸激素与鸟类生存率降低有关，但这种联系的机制尚不清楚。一种假说是睾丸激素缩短了端粒。端粒是保护染色体末端的DNA短序列，可以影响生存。压力也会缩短端粒长度，而端粒缩短与寿命缩短有关。研究人员操纵了东部蓝知更鸟的育雏大小，以改变父母的照顾，侵略和压力，这些都可以与睾丸激素水平相互作用。他们将确定家庭规模、行为和激素如何影响端粒长度，从而影响寿命和生存。研究人员还将为当地高中生制定教育计划，学习行为生态学和生理学领域的基本概念。研究人员发现，蓝知更鸟在睾丸激素的产生方面存在相当大的个体差异。紧张与重要的、与健康有关的行为有关。提高睾丸激素水平的代价也有充分的证据。虽然已经做了很多工作来阐明行为和调节它们的激素机制之间的关系，但目前关于行为和生理联系如何与影响生存的机制（即，端粒长度和端粒损失）。研究人员将分析先前收集的血液样本，以测量睾酮、皮质酮和端粒长度。他们将这些生理测量与先前记录的行为数据相关联。通过将睾酮介导的昂贵行为与端粒长度联系起来，这项研究将采取综合方法来回答跨越行为生态学，内分泌学和进化学领域的问题。数据将在俄克拉荷马州州立大学存档，数据请求将在研究人员批准后完成。

Animals can benefit by having many offspring that survive and reproduce. To increase offspring survival, parents may provide extensive parental care and exhibit aggression towards predators or intruders. However, raising and defending a large family can increase stress on parents. Additionally, hormones often regulate expression of behaviors. For example, testosterone is associated with reduced parental care and increased aggression in many birds. High levels of testosterone have been linked to reduced survival in birds, but the mechanisms underlying this link are unknown. One hypothesis is that testosterone shortens telomeres. Telomeres are short sequences of DNA that protect the ends of chromosomes and can affect survival. Stress can also shorten telomere lengths, and shorter telomeres have been associated with reduced lifespan. The researchers have manipulated brood sizes of eastern bluebirds to alter parental care, aggression, and stress, which can all interact with testosterone levels. They will determine how family size, behavior, and hormones affect telomere lengths to impact longevity and survival. The researchers will also develop education programs for local high school students to learn fundamental concepts in the fields of behavioral ecology and physiology.The researchers have found that bluebirds have considerable individual variation in testosterone production. Testosterone is implicated in important, fitness-related behaviors. The costs of elevating testosterone are also well-documented. Although much has been done to elucidate relationships between behaviors and the hormonal mechanisms that regulate them, there is currently very little information about how behavioral and physiological links might be tied to mechanisms that affect survival (i.e., telomere lengths and telomere loss). The researchers will analyze previously collected blood samples to measure testosterone, corticosterone, and telomere lengths. They will relate these physiological measurements to previously recorded behavioral data. By linking costly behaviors mediated by testosterone to telomere lengths, this study will take an integrative approach to answering questions that span the fields of behavioral ecology, endocrinology, and evolution. Data will archived at Oklahoma State University and requests for data will be fulfilled upon approval of the researchers.