Dissertation Research: Do egg size effects cascade through salamander ontogeny? Allometric engineering of maternal provisioning

雌性对两栖动物后代的投资在不同的物种、个体和环境中差异很大。然而，更大的蛋是以产生更少的后代为代价的。此外，自然界中卵的大小变化往往伴随着幼虫形态和行为（表型）的差异。卵大小和幼虫表型之间的机制关系仍然存在争议，因为物种在遗传和环境诱导的性状上也存在差异。本项目将通过实验研究蝾螈卵的大小对其幼虫表型的影响，其中在池塘繁殖物种入侵溪流后，卵的大小进化地增加了一倍。通过手术从胚胎中去除卵黄，母体投资对表型的影响将根据溪流适应进行评估。具体来说，我们将研究鸡蛋大小对孵化时间和阶段、身体大小和形状、逃逸性能和存活率以及变态时间的影响。这项研究的智力价值包括开发一种强大的实验研究技术，用于研究两栖动物生活史进化的主要组成部分，可以帮助确定对卵大小做出反应的相关特征。更广泛的影响包括培训一名研究生，六名具有不同背景的本科生，并广泛传播结果-从YouTube到地方，国家和国际会议，并在同行评审的期刊上发表。

Maternal investment in amphibian offspring varies a great deal among species, individuals and environments. However, larger egg size comes at the cost of producing fewer offspring. Furthermore, egg size variation in nature is often accompanied by differences in larval morphology and behavior (phenotype). The mechanistic relationship between egg size and larval phenotype remains controversial because species also differ in genetic and environmentally-induced traits. This project will examine experimentally the effects of egg size on larval phenotype in salamanders in which egg size evolutionarily doubled after a pond breeding species invaded streams. By surgically removing yolk from embryos, the effect of maternal investment on the phenotype will be assessed in light of stream adaptations. Specifically, we will examine egg size effects on hatching time and stage, body size and shape, escape performance and survival rates, and time to metamorphosis.The intellectual merit of this research includes developing a powerful experimental research technique for studying a major component of amphibian life history evolution that can help identify correlated traits that respond to egg size. Broader impacts include training of a graduate student, six undergraduates with diverse backgrounds, and broad dissemination of the results - from YouTube to local, national and international meetings, and publication in peer-reviewed journals.