DISSERTATION RESEARCH: Condition-dependent ornaments and parental care

在照顾同等价值的后代时，父母可以从有限资源的平等分配中获益。然而，如果一些后代比其他后代更有前途，父母可能会从将资源转移到高价值的个体中受益。在鸟类中，雏鸟的嘴部颜色鲜艳，可以让父母评估雏鸟的相对质量。例如，在雏鸟中，黄色嘴巴颜色的强度与环境呈正相关，父母会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，交叉培育部分雏鸟的研究将检验孵化前和孵化后环境对嘴色的相对贡献。如果饲养环境解释了大部分差异，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）。如果亲子关系解释了大多数颜色变化，这将表明，颜色可能反而揭示了由遗传或蛋的特征（母体效应）驱动的雏鸟品质。第二个实验检验了一种吸血昆虫寄生虫及其传播的一种病毒对雏鸟口腔颜色的影响。如果口腔颜色与雏鸟健康有关，暴露于寄生虫和病毒的雏鸟的黄色应该比未暴露的雏鸟少，颜色应该积极预测雏鸟抵御感染的能力。这两项研究共同研究了雏鸟嘴的颜色如何整合过去挑战的信息，并预测未来的恢复能力，以及识别这种信号系统可能的遗传和孵化前的限制。这个项目将提供一些见解，解释为什么父母会从偏爱某些后代中受益，以及确定野生鸟类感染存活的相关因素。该项目的更广泛影响包括培训一名研究生，指导一名本科生，并为俄克拉何马州自然历史博物馆和俄克拉何马市动物园的展览做出贡献。

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.