Dissertation Research: Reciprocal interactions between host behaviors, steroid hormones, and parasites

在人类和非人类动物中，行为影响着遇到寄生虫并被寄生虫感染的风险。例如，一个人吃的食物的类型，一个人旅行的地方，以及一个人从事的危险行为，都是确定寄生虫风险的重要因素。行为和寄生之间相互作用的另一个重要但研究较少的方面探索了寄生虫在感染后如何改变宿主行为。人(例如弓形虫)和非人类动物的寄生虫可以改变宿主的行为，而且似乎是通过改变宿主的大脑化学或激素水平来做到这一点。例如，两种感染加州千里鱼的吸虫寄生虫增加了鱼的危险行为频率，其中一种寄生虫与鱼大脑化学物质的变化有关。这项研究将探索千里鱼的行为和激素水平如何影响寄生虫的遭遇和感染率，以及感染如何改变鱼的行为和激素水平。这些问题将通过实验室行为实验、剑鱼自然栖息地的野外实验和分子技术来探索。研究人员预测，群居较少、活动较多的千里鱼更频繁地遇到寄生虫，感染会改变宿主的雄激素、雌激素和糖皮质激素(激素类型)的水平，使鱼变得更大胆、更无社交和更活跃。这个项目很重要，因为寄生虫在行为研究中通常被忽视，但很可能对整个动物界的宿主行为和生理产生非常重要的影响。此外，负责这个项目的博士生有很强的外展历史。她将让本科生和高中生参与这个项目，这笔助学金将允许她向学生传授测量激素水平的分子技术，以及生态和行为技术。

In human and non-human animals, behavior influences the risk of encountering and becoming infected by parasites. For example, the types of food one eats, places one travels, and risky behaviors one engages in are all important in determining parasite risk. Another important, but less well studied, aspect of the interaction between behavior and parasitism explores how parasites change host behavior after infection. Parasites of people (for example, Toxoplasma gondii) and non-human animals can change the behavior of their hosts, and appear to do so by changing the host's brain chemistry or hormone levels. For example, two trematode parasites infecting California killifish increase the frequency of risky behaviors in the fish, and one of these parasites is associated with changes in the fish's brain chemistry. This study will explore how killifish behavior and hormone levels influence encounter and infection rates with parasites, and how infection changes the fish's behavior and hormone levels. Laboratory behavioral experiments, field experiments in the killifish's natural habitat, and molecular techniques will be used to explore these questions. The researchers predict that less social, more active killifish encounter parasites more often, and that infection changes host levels of androgens, estrogens, and glucocorticoids (types of hormones) and makes the fish more bold, asocial, and active. This project is important because parasites are commonly overlooked in behavioral studies, yet are likely to have very important implications for host behavior and physiology across the animal kingdom. Additionally, the PhD student running this project has a strong history of outreach. She will involve undergraduate and high school students in this project, and this grant will allow her to teach the students molecular techniques for measuring hormone levels, in addition to ecological and behavioral techniques.