How Changes in Diet Can Enable Caterpillars to Overcome Parasite Infection

迈克尔·S·辛格，提案IOS-0744676改变饮食如何使毛虫克服寄生虫感染摄食行为的改变可以使个体动物治愈寄生虫感染或其他生理痛苦。所有动物都有免疫防御，这种免疫防御可能会根据个体的饮食而改变强度。此外，毛虫等食草动物可能会通过摄取和积累它们所吃植物中的有毒化学物质来杀死它们的寄生虫。本研究项目将探讨毛熊毛虫的这两种抗寄生虫行为方式。这一物种被怀疑是从以前的研究中通过它的摄食选择来抵御自然寄生虫。首先，行为实验将描述被实验寄生的毛虫与未被寄生的毛虫的饮食选择的关系。其次，为了评估特定饲料在抵抗寄生虫方面的作用，将测试寄生和未寄生的毛虫在不同饲料上的存活率。第三，生理学实验将评估这些饲料对毛毛虫对寄生虫的免疫反应的影响。最后，为了分析没有免疫系统的毛毛虫饮食的直接影响，将寄生虫饲养在反映不同毛毛虫饮食的人工饲料上。新感染了潜在致命寄生蝇Exorista Mella的毛虫预计会选择营养饮食来增强它们的免疫抵抗力。这种机制预计将为毛毛虫带来最小的生理成本。然而，受到晚期寄生虫感染威胁的毛虫预计会选择富含天然植物毒素的食物，称为吡咯里西丁生物碱。对于毛虫来说，摄取异常大量的生物碱预计会造成生理上的代价，因此被用作最后的手段。这项研究的更广泛的影响包括培训不同的学生和博士后将行为、生理学和生态学与动物健康联系起来。通过公开演讲，该项目还将教育公众关于动物健康、行为和环境之间的科学联系。

Michael S. Singer, Proposal IOS-0744676How changes in diet can enable caterpillars to overcome parasite infectionChanges in feeding behavior can enable individual animals to cure themselves of parasite infections or other physiological distress. All animals have immunological defenses that can potentially change in strength based on an individual's diet. In addition, herbivores such as caterpillars may kill their parasites by ingesting and accumulating toxic chemicals found in the plants they eat. This research project will investigate these two means of anti-parasite behavior by the woolly bear caterpillar Grammia geneura. This species is suspected from previous study to ward off natural parasites through its feeding choices. First, behavioral experiments will characterize the dietary choices of experimentally parasitized caterpillars in relation to unparasitized caterpillars. Second, to evaluate the role of specific diets in resistance against parasites, the survival of parasitized and unparasitized caterpillars on different diets will be tested. Third, physiological experiments will evaluate the effects of these diets on the caterpillar's immune response to parasites. Finally, to analyze direct effects of caterpillar diet without the immune system, the parasites will be raised on artificial diets that reflect different caterpillar diets. Caterpillars newly infected by the potentially lethal, parasitic fly Exorista mella, are expected to choose a nutritious diet to enhance their immunological resistance. This mechanism is expected to carry minimal physiological costs for the caterpillar. However, caterpillars threatened by late-stage parasitic infections are expected to choose a diet rich in natural plant toxins called pyrrolizidine alkaloids. Ingesting unusually large quantities of alkaloids is expected to be physiologically costly for the caterpillar, and thus used as a last resort. The broader impacts of this research include training diverse students and a post-doctoral fellow in linking behavior, physiology, and ecology to animal health. Through public presentations, this project will also educate the public about the scientific link between animal health, behavior, and the environment.