Social Environment, Hormones, and Ontogenetic Carry-Over Effects on Male Reproductive Phenotypes in a Polymorphic bird

雄性动物通常表现出相当大的可塑性的行为策略和信号，他们用来获得配偶。 例如，在许多鸟类种群中，一些雄性繁殖时羽毛鲜艳，而另一些繁殖时羽毛相对暗淡。 一般认为，性特征的可塑性表达取决于内在（身体状况）和外在（社会互动）的暗示，这使得雄性可以根据自己的质量和交配成功的相对可能性来调整他们对信号的投资，因此这些特征诚实地向同种发出雄性质量的信号。 然而，将这些线索转化为男性性特征的机制，从而允许性特征的可塑性表达，却知之甚少。 本研究旨在探讨红背细尾莺雄性生殖表型灵活表达的机制。 特别是，该项目将通过实验确定身体状况、社会环境和压力对影响男性生殖类型的激素的影响。 这项工作将联合收割机的功能和机制分析相结合，并将把表型可塑性和性信号的研究推向新的方向。 此外，该研究还将探讨早期生活环境对男性状况和生殖类型的影响，这是一个前沿研究领域，因为最近人们认识到早期发育对成年性状有重要影响。 这些结果将对性信号进化的理论模型产生重大影响。 本研究也将直接有助于两名研究生和众多本科生的培养。 本科生培训将包括一个新颖的实习计划，将来自美国大学的学生与澳大利亚学生配对进行合作研究。 因此，该项目将涉及研究经验的各个方面，从项目设计到出版，并为他们提供丰富的国际经验。

Male animals typically show considerable plasticity in the behavioral tactics and signals that they use to obtain mates. For example, in many bird populations, some males breed in bright plumage while others breed in relatively dull plumage. It is generally thought that plastic expression of sexual traits depends on both intrinsic (body condition) and extrinsic cues (social interactions), allowing males to adjust their investment in signals according to their quality and relative likelihood of mating success, and consequently that such traits honestly signal male quality to conspecifics. However, the mechanisms that translate these cues to male sexual traits, and thereby allow for plastic expression of sexual traits, are poorly understood. This research will examine the mechanisms of flexible expression of male reproductive phenotypes in the red-backed fairy wren (Malurus melanocephalus). In particular, this project will determine experimentally the effects of physical condition, social environment and stress on the hormones that affect male reproductive type. This work will combine both functional and mechanistic analyses, and will push the study of phenotypic plasticity and sexual signals in new directions. In addition, the research will explore carry-over effects of early life environment on male condition and reproductive type, a cutting-edge field of research emerging from the recent acknowledgement that early development can have important effects on adult traits. These results will have major implications for theoretical models of the evolution of sexual signals. This research also will contribute directly to the training of two graduate students and numerous undergraduates. Undergraduate training will include a novel internship program that will pair students from American universities with Australian students to conduct collaborative research. Thus, this project will involve undergraduates in all aspects of the research experience, from project design through publication, as well as giving them an enriching international experience.