DISSERTATION RESEARCH: Energetic Regulation of Seasonal Sickness Behaviors

一旦感染，动物会表现出一系列的行为，称为“病态行为”。“对季节性繁殖物种的疾病行为的研究表明，动物对感染的反应程度随季节而变化。疾病行为的季节性调节可能是一种避免过度消耗能量或错过繁殖机会的机制，但抑制这些行为的表达可能会使生物体处于无法清除感染的更大风险中。因此，一个有机体表达疾病的程度将对其生存和繁殖成功产生深远的影响。当比较不同的研究时，出现了一个明确的模式，即疾病行为在动物能量储备最低的季节减弱;然而，这种关系的因果关系尚未经过实验测试。该项目的工作假设是，疾病行为的季节性变化是由于能量储存的季节性变化。本研究的具体目的是：1）确定食物可获得性的季节性变化对疾病行为的贡献，2）确定代谢激素如何影响疾病行为的变化，3）评估食物可获得性和代谢激素对直接介导季节性饲养的西伯利亚仓鼠疾病行为的内分泌和免疫因素的实验操作的贡献。对调节疾病行为表现的生理信号的理解将增强我们对环境条件如何影响动物对感染的反应的知识。这项研究的结果将有助于目前的举措，以了解疾病的易感性作为一个功能的病原体流行（即，疾病生态学）和宿主免疫功能（即，生态免疫学）。此外，这项工作提供了机会，让不同的本科生参与研究培训，并将继续这样做，因为这些项目已经完成。数据将提供研究数据复杂（RDC），http://pervasive.iu.edu/hps/rdc

Upon infection, animals display a collection of behaviors called "sickness behaviors." Studies of sickness behaviors in seasonally breeding species have shown that the magnitude of an animal's response to infection varies across seasons. Seasonal modulation of sickness behaviors may be a mechanism to avoid over-expending energy or missing a reproductive opportunity, but suppressing the expression of these behaviors may put an organism at greater risk of not being able to clear an infection. Therefore, the degree to which an organism expresses sickness will have profound effects on its survival and reproductive success. When comparing across studies, a clear pattern emerges in that sickness behaviors are attenuated in the season in which an animal has the lowest energy reserves; however, the causative nature of this relationship has not been tested experimentally. The project's working hypothesis is that seasonal variation in sickness behaviors is due to seasonal variation in energy stores. The specific aims of the research are to: 1) determine the contributions of seasonal changes in food availability on sickness behaviors, 2) determine how metabolic hormones influence variation in sickness behaviors, and 3) evaluate the contributions of experimental manipulations of food availability and metabolic hormones on endocrine and immunological factors that directly mediate sickness behavior in seasonally breeding Siberian hamsters. An understanding of the physiological signals that act to modulate the display of sickness behaviors will enhance our knowledge of how environmental conditions affect how an animal responds to an infection. The results of this research will contribute to the current initiatives to understand disease susceptibility as a function of pathogen prevalence (i.e., disease ecology) and host immune function (i.e., ecoimmunology). Additionally, this work has provided opportunities to engage diverse undergraduates in research training and will continue to do so as these projects are completed.Data will be made available on Research Data Complex (RDC), http://pervasive.iu.edu/hps/rdc