Metabolic Energy Costs of Development in Feeding and Non-Feeding Larvae

幼虫发育的能量学在生活史模型中受到了相当大的关注。许多关于母体能量分配给后代的理论考虑已经发表，以描述卵大小对决定幼体-幼体在变态时的大小和年龄的重要意义。然而，母体将能量分配给卵子只是发育能量学方程式的一半。另一半是幼虫从胚胎发育到幼虫所利用的实际能量，这方面的发育能量学在文献中受到的关注要少得多。理解将大量能量分配给几个大卵(产生一个大的非摄食幼虫)或将很少的能量分配给许多小卵(产生一个小的摄食幼虫)的选择利弊，关键在于准确评估这些幼虫在特定环境中发育的能量成本。不同形态幼虫之间的发育能量学比较容易被不同幼虫之间的系统发育距离所混淆。然而，少数无脊椎动物物种产生了多种发育形式，为比较发育能量学提供了一个理想的系统。该项目重点描述了单一物种--贝氏链球藻的摄食和非摄食幼虫发育的能量成本。对多毛链球藻发育的代谢能量成本的研究将涉及决定幼虫发育期间能量利用的四个生物功能水平：发育模式(摄食和不摄食)、个体变异性(基因)、环境变异性(温度和食物)和蛋白质代谢(蛋白质组学)。了解发育能量成本的这四个决定因素将提供一个比较框架，用于考虑当前生活史模型中摄食和不摄食幼虫形式的选择利弊，这些模型将幼虫代谢需要的估计纳入幼虫变态时的年龄和大小估计。该项目将首次对离散的生化机制(蛋白质周转)进行检验，以解释发育过程中能量代谢的差异(包括个体和环境变异性)，并可能表明代谢调节的潜在遗传成分，涉及海洋无脊椎动物幼虫摄食和非摄食发育模式的演变。

The energetics of larval development has received considerable attention in life-history models. Numerous theoretical considerations of the allocation of maternal energy to offspring have been published to describe the important implications of egg-size for determining the size and age of the larvae-juvenile at metamorphosis. However, the maternal allocation of energy to eggs is only one half of the developmental energetics equation. The other half is the actual amount of energy that a larva will utilize as it develops from an embryo to a juvenile, and this aspect of developmental energetics has received far less attention in the literature.The key to understanding the selective advantages or disadvantages of allocating lots of energy to a few big eggs (producing a large non-feeding larvae), or very little energy to lots of little eggs (producing a small feeding larvae), lies in an accurate assessment of the energy costs of development of each of these larval forms within a specific environment. The comparison of developmental energetics between different larval forms can be easily confounded by the phylogenetic distance between different larvae. However, a few invertebrate species produce multiple developmental forms and provide an ideal system for comparative developmental energetics. This project focuses on describing the energy costs of development in the feeding and non-feeding larvae of a single species, the spionid polychaete Streblospio benedicti.An investigation of the metabolic energy costs of development in the polychaete Streblospio benedicti will address four levels of biological function that determine energy utilization during larval development: developmental mode (feeding and non-feeding), individual variability (genotype), environmental variability (temperature and food), and protein metabolism (proteomics). Understanding these four determinants of developmental energy costs will provide a comparative framework for considering the selective advantages and disadvantages of feeding and non-feeding larval forms in current life-history models that incorporate estimates of larval metabolic requirements into the estimates of larval age and size at metamorphosis. This project will produce the first examination of a discrete biochemical mechanism (protein turnover) to account for differences in energy metabolism during development (both in terms of individual and envirom-nental variability) and potentially indicate an underlying genetic component of metabolic regulation involved in the evolution of feeding and non-feeding modes of development in marine invertebrate larvae.