Mechanisms and Evolutionary Consequences of a Reproduction-Immunity Tradeoff

项目摘要 所有生物体都必须同时平衡多种相互竞争的需求， 生理资源。这可能导致性状之间的冲突，推动生理和进化 权衡对感染的防御和繁殖能力都受到强大的自然选择的影响 作为进化适应性的重要贡献者，两者都需要能量， 两者之间几乎普遍存在于植物和动物中，包括那些与公共卫生有关的植物和动物。 重要性然而，尽管它们无处不在和重要性，令人惊讶的是， 生殖免疫权衡的基础。这种知识上的缺陷限制了关于 进化过程，并适用于干预控制昆虫的能力的实际限制 农业或公共卫生方面的害虫。拟议中的项目将使用易于控制的模型昆虫 果蝇确定生殖投资限制的机制 免疫性能，探索权衡的进化意义，并提供罕见的 了解生命史权衡如何产生和维持。该项目将测试 多效性的激素理论，它假定内分泌信号可以作为一个主调节器， 塑造生活史权衡，重点是昆虫保幼激素（JH）。初步实验将 确定响应交配的JH信号传导的时间动力学和定量关系 JH信号强度和免疫抑制程度之间的关系。后续实验将 确定JH抑制免疫的机制，寻求确定新的调节机制， 过程，测试一个假设，即权衡可以通过对蜂窝基础设施的压力而产生， 确定免疫抑制是否可以与生殖投资脱钩。额外 实验将测试JH信号传导中自然发生的遗传变异是否决定了自然的 表型变异的大小的生殖免疫权衡和是否充满活力 繁殖产出所需的投资直接限制了免疫防御的质量。数据 将包括深入研究的焦点系统，并将揭示原则，可以 在不同的系统中普遍存在。

PROJECT SUMMARY All organisms must simultaneously balance multiple competing demands on their energetic and physiological resources. This can result in conflict among traits, driving physiological and evolutionary tradeoffs. Defense against infection and reproductive capacity are each under strong natural selection as important contributors to evolutionary fitness, both are energetically demanding, and tradeoffs between the two are nearly universal in plants and animals, including those with public health importance. Yet despite their ubiquity and importance, surprisingly little is known about the mechanistic basis for reproduction-immunity tradeoffs. This shortcoming in knowledge limits inference about the evolutionary process and applies practical limitations on the capacity for interventions to control insect pests in agricultural or public health contexts. The proposed project will use the tractable model insect Drosophila melanogaster to determine mechanisms by which reproductive investment constrains immune performance, exploring the evolutionary implications of the tradeoff and providing rare understanding of how life history tradeoffs arise and are maintained. The project will test of the hormonal theory of pleiotropy, which posits that endocrine signaling can act as a master regulator to shape life history tradeoffs, with a focus on insect Juvenile Hormone (JH). Initial experiments will determine the temporal kinetics of JH signaling in response to mating and the quantitative relationship between JH signal intensity and degree of immune suppression. Subsequent experiments will determine the mechanisms by which JH suppresses immunity, seeking to identify novel regulatory processes, testing a hypothesis that the tradeoff can arise through strain on cellular infrastructure, and determining whether immunosuppression can be decoupled from reproductive investment. Additional experiments will test whether naturally occurring genetic variation in JH signaling determines natural phenotypic variability in the magnitude of the reproduction-immunity tradeoff and whether energetic investment required for reproductive output directly limits the quality of immune defense. The data obtained will comprise an in-depth study of the focal system and will reveal principles that can be generalized across diverse systems.