Dissertation Research: Antioxidant physiology, alternative reproductive strategies, and the information content of pigment based ornaments: A life history perspective

雄性的装饰会影响它们能否接触到配偶。鉴于装饰品的表达在生理上是昂贵的，精心制作的装饰品可能仅限于状况良好的个人，提供诚实的？对雌性来说，这是质量的信号。然而，这可能并不总是正确的，因为雄性可能不得不在不同的因素之间分配资源，比如装饰和自我维持或父母照顾。这项拟议的研究试图将性装饰品理解为生活史投资，其发展可能会与其他选择进行权衡。具体地说，抗氧化能力的分配可能会在吸引力和自我维持之间进行权衡，这种权衡取决于生活史。当抗氧化能力被身体活动或免疫反应中产生的促氧化剂压倒时，就会发生氧化应激，这可能会导致衰老和疾病的发生。表达类胡萝卜素和黑色素为基础的色素装饰物可能会增加交配成功率，但也会消耗具有抗氧化能力的分子，加剧对配偶的昂贵竞争，潜在地增加氧化应激，抑制存活率和亲本表现。这项研究将：(1)采用纵向抽样的方法来探索加州黄莺(Setophaga Petechia Brewsteri)中表达色素沉着是否会增加氧化应激并降低亲代表现；以及(2)使用比较的方法来探索墨西哥红树林林莺S.Petechia(S.P.bryanti)的色素沉着与氧化应激是否存在不同的相关性，这些亚种表现出与生活在快速生活的加州鸣鸟相比的“缓慢”生活史(存活时间长、窝卵小、非迁徙)。由于红树林林莺的生存价值更高，预计它们将在发出氧化状态信号时表现出更大的“诚实”。通过从生活史的角度来看，这项工作为理解性信号系统的复杂性提供了一个新的概念框架。更广泛的影响包括了解影响特别关注物种繁殖成功的因素，以及与墨西哥研究人员建立合作。

Male ornamentation influence whether or not they gain access to mates. Given that ornaments are physiologically costly to express, elaborate ornaments may be restricted to individuals in good condition, providing an ?honest? signal of quality to females. However this may not always be true, as males may have to allocate resources between different factors such as ornamentation versus self-maintenance or parental care. The proposed research seeks to understand sexual ornaments as life history investments, whose development may tradeoff against other alternatives. Specifically, allocation of antioxidant capacity may mediate a tradeoff between attractiveness and self-maintenance, with balance of this tradeoff depending on life history. Oxidative stress occurs when antioxidant capacity is overwhelmed by the production of pro-oxidants through physical activity or immune response, which can then lead to onset of aging and diseases. Expressing carotenoid and melanin-based pigmented ornaments may increase mating success, but also consume molecules with antioxidant capacity and intensify expensive contests over mates, potentially elevating oxidative stress and suppressing survival and parental performance. This research will: (1) employ longitudinal sampling to explore whether expressing pigmentation increases oxidative stress and reduces parental performance in California yellow warblers (Setophaga petechia brewsteri); and (2) use a comparative approach to explore if pigmentation correlates differently with oxidative stress in the Mexican, mangrove warbler subspecies of S. petechia (S. p. bryanti), which displays a "slow' life history (long survival, small clutch size, non-migratory) versus in "fast" lived California warblers. Mangrove warblers are predicted to display greater "honesty" in signaling oxidative status, due to greater value of survivorship. By taking a life history perspective, this work provides a novel conceptual framework for understanding complexities of sexual signaling systems. Broader impacts include understanding factors influencing reproductive success in a Species of Special Concern and forging collaboration with Mexican researchers.