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

雄性的纹饰影响着它们能否获得配偶。考虑到装饰品在生理上表达是昂贵的，精心制作的装饰品可能仅限于状况良好的个人，提供一种“诚实”的感觉。对雌性的质量信号。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，比如装饰与自我维护或亲代照顾。拟议的研究试图将性装饰理解为生活史投资，其发展可能会与其他选择相权衡。具体来说，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，这种权衡的平衡取决于生命史。当抗氧化能力被身体活动或免疫反应产生的促氧化剂所压倒时，就会发生氧化应激，从而导致衰老和疾病的发生。表达类胡萝卜素和基于黑色素的色素装饰物可能会提高交配成功率，但也会消耗具有抗氧化能力的分子，加剧昂贵的配偶竞争，潜在地提高氧化应激，抑制生存和亲代表现。本研究将：(1)采用纵向抽样方法探讨色素沉着表达是否会增加加州黄莺（Setophaga petechia brewsteri）的氧化应激并降低亲代性能；(2)使用比较方法探索墨西哥红树林莺亚种的色素沉着与氧化应激的相关性是否不同，红树林莺亚种表现出“缓慢”的生活史（生存时间长，窝数小，不迁徙），而加利福尼亚林莺则表现出“快速”的生活。据预测，红树林林莺在氧化状态的信号中表现得更“诚实”，因为生存的价值更高。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，并与墨西哥研究人员建立合作关系。

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.