DISSERTATION RESEARCH: Condition-dependent ornaments and parental care

在照顾同等价值的子女时，父母可以从有限资源的平等分配中受益。然而，如果一些孩子比其他孩子更有前途，父母可能反而会受益于将资源转移到高价值的人身上。在鸟类中，雏鸟的嘴部颜色鲜艳，这可能会让父母评估雏鸟的相对质量。例如，在羽舍麻雀中，黄色嘴色的强度与条件呈正相关，父母给更多的黄色雏鸟提供更多的食物。这个项目进一步研究了颜色和雏鸟健康之间的关系。首先，一项对部分雏鸟进行交叉培养的研究将考察孵化前后环境对嘴部颜色的相对贡献。如果饲养环境可以解释大多数差异，这将表明颜色整合了孵化后条件的信息(例如，饮食、寄生虫感染)。如果亲子关系可以解释大部分的颜色变化，这将表明颜色可能会显示出由基因或卵子特征驱动的筑巢特性(母系效应)。第二个实验考察了一种吸血昆虫寄生虫及其传播的病毒对雏鸟口腔颜色的影响。如果嘴的颜色与雏鸟的健康有关，那么暴露在寄生虫和病毒中的雏鸟应该比没有接触的雏鸟的黄色要少，而且颜色应该可以积极地预测雏鸟抵抗感染的能力。这两项研究一起研究了雏鸟的嘴色如何整合有关过去挑战的信息和预测未来的弹性，以及确定可能的遗传和孵化前对该信号系统的限制。这个项目将提供关于为什么父母从偏爱某些后代中受益的见解，以及识别野生鸟类感染存活的相关因素。该项目的更广泛影响包括对研究生的培训，对本科生的指导，以及对俄克拉荷马州自然历史博物馆和俄克拉何马市动物园展品的贡献。

When caring for offspring of equal value, parents may benefit from equal allocation of limited resources. However, if some offspring are more promising than others, parents may instead benefit from diverting resources to high-value individuals. In birds, nestlings display brightly colored mouth parts that may allow parents to assess the relative quality of chicks. In nestling house sparrows, for example, the intensity of yellow mouth coloration is positively associated with condition, and parents deliver more food to more yellow nestlings. This project further examines the relationship between coloration and nestling health. First, a study in which partial broods are cross-fostered will examine the relative contribution that pre- and post-hatching environment make to mouth color. If rearing environment explains most variation, this will suggest that color integrates information about post-hatching conditions (e.g. diet, parasite infection). If parentage explains most color variation, this will suggest that colors may instead reveal nestling qualities driven by genetics or characteristics of the egg (maternal effects). A second experiment examines the effects of a blood-sucking insect parasite, and a virus that it transmits, on nestling mouth color. If mouth colors are associated with nestling health, nestlings exposed to parasites and virus should be less yellow than nestlings not exposed, and color should positively predict the ability of nestlings to withstand infection. Together, these two studies examine how nestling mouth color integrates information about past challenges and predicts future resilience, as well as identifying possible genetic and pre-hatching constraints on this signaling system. This project will offer insights into why parents benefit from favoring certain offspring as well as identify correlates of infection survival in wild birds. Broader impacts of this project include training of a graduate student, mentorship of an undergraduate student and contributions to exhibits at the Oklahoma Museum of Natural History and to the Oklahoma City Zoo.