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

University Of California-Riverside, Riverside CA

Investigators

Abstract

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.