Reproductive Allocation of Specific Nutrients: The Effects of Foraging, Life History, and Flight

许多生物，包括蝴蝶和其他一些昆虫，有非常不同的幼虫和成虫阶段。生活方式的许多方面，包括食物来源，在这些生命阶段有所不同。不同物种可获得的成虫食物的质量和数量不同，导致不同物种之间成虫和幼虫食物在产卵和成虫存活或生活史性状中的相对重要性不同。这些来自不同生命阶段的营养物质的重要性模式决定了产蛋的时间和鸡蛋的营养成分。我们对来自幼虫和成虫来源的卵的营养分配的研究旨在了解对进食和繁殖习惯可能组合的限制，以及物种在不同环境中可能的持久性。我们将利用食物来源稳定碳同位素比率的自然变化作为追踪用于制作鸡蛋的营养来源的工具。我们将讨论三个假设。第一篇论文阐述了六种鳞翅目昆虫在成虫食物的可得性和质量上的自然差异是如何分配的。我们将确定分配给繁殖的营养来源（即幼虫食物与成虫食物）是否因成虫喂养生态而异。第二个假设涉及两个营养池的化学特性。这一信息使我们能够了解控制幼虫和成虫在卵中相对使用膳食营养素的生理机制。第三种假说探讨了生态因素，即花蜜可得性和飞行时间的变化，如何影响物种内的分配模式。一个物种的个体将被置于不同的食物供应条件下，并将被诱导每天飞行不同长度的时间。将分析这些个体的卵的稳定碳同位素组成，以了解繁殖分配如何与摄食条件和飞行消耗相互作用。这个实验允许我们的结果外推到现场设置。我们的研究结果将为营养生态学、能量代谢和繁殖之间的关系提供信息。这些信息对蝴蝶和其他昆虫具有特别的实用价值，其中许多物种受到威胁或在保护生物学中是重要的指标。然而，更一般地说，拟议的研究将为进一步研究营养动力学和生活史进化提供重要的概念和经验基础。

Many organisms, including butterflies and some other insects, have very different larval and adult life stages. Many aspects of the life style, including food sources, differ between these life stages. Species differ in the quality and quantity of adult food available to them, resulting in differences among species in the relative importance of adult and larval food in egg production and adult survival, or life history traits. These patterns of importance of nutrients from different life stages determine the timing of egg production, and the nutrient make-up of the egg. Our work on nutrient allocation to eggs from larval and adult sources is aimed at understanding the constraints on possible combinations of feeding and reproductive habits, as well as the likely persistence of species in different environments.We will use natural variation in stable carbon isotope ratios of food sources as a tool for tracing the origin of nutrients used to make eggs. We will address three hypotheses. The first addresses how allocation varies among six species of Lepidoptera that differ naturally in availability and quality of adult food. We will determine if the source of nutrients allocated to reproduction (i.e., larval food vs. adult food) varies with adult feeding ecology. The second hypothesis concerns the chemical identity of the two nutrient pools. This information allows us to understand the physiological mechanisms governing the relative use of larval and adult dietary nutrients in eggs. The third hypothesis explores how ecological factors, namely variation in nectar availability and time spent in flight, may affect allocation patterns within a species. Individuals of one species will be kept under varying conditions of food availability, and will be induced to fly for varying lengths of time daily. Stable carbon isotope composition of eggs from these individuals will be analyzed to yield understand how allocation to reproduction interacts with feeding conditions and flight expenditure. This experiment allows the extrapolation of our results to a field setting.The results of our proposed work will provide information on the relationships among nutritional ecology, energy metabolism, and reproduction. This information has particular practical value for butterflies and other insects, many species of which are threatened or are important indicators in conservation biology. More generally, however, the proposed research will provide an important conceptual and empirical foundation for further work on both nutrient dynamics and the evolution of life histories.