NSF Postdoctoral Fellowship in Biology FY 2017: Do sick frogs increase reproductive investment? A behavioral and physiological examination of the terminal investment hypothesis

这是美国国家科学基金会生物学博士后研究奖学金，隶属于“扩大生物学中代表性不足群体的参与”项目。这位名叫塔利辛·哈蒙德（Talisin Hammond）的研究员正在匹兹堡大学进行研究，并接受培训，以增加生物学中代表性不足的群体的参与，他的导师是科里·理查兹-扎维基（赞助科学家）。本研究探讨了多种青蛙的生殖行为和生理是如何受到壶菌病的影响的，壶菌病是一种真菌疾病，已经摧毁了许多两栖动物种群。除了提高我们对这种疾病如何影响两栖动物的理解之外，这种疾病目前受到许多环境因素的高度威胁，这项工作还阐明了疾病的亚致死效应在种群动态和进化过程中的作用。作为这个项目的一部分，他正在与一家自然历史博物馆合作，用素描笔记的方法向学生团体教授科学知识。他还在设计一个基于研究的教育模块，该模块将免费提供，并与一个在线网络合作，寻找对其实施感兴趣的教育工作者。最后，他还指导不同的本科生。野生动物疾病既通过死亡率直接影响种群，也通过对宿主生物学的亚致命性变化间接影响种群。疾病导致的死亡可能是毁灭性的，但行为和生理上的亚致命变化也有可能对种群施加巨大压力。终端投资假说认为，未来繁殖潜力下降的动物应该更多地投资于即时繁殖，并预测寿命下降的患病动物应该提高繁殖努力，而易感性更高的物种应该更多地增加繁殖努力。这位研究员的研究正在验证这一假设，重点是壶菌病作为疾病的病原体。这种疾病杀死两栖动物的过程比其亚致死影响更容易理解，很少有研究通过实验描述壶菌病如何影响生殖行为和生理。该项目使用三种具有不同疾病易感性的同类青蛙，使用呼叫录音、行为选择测试和激素操作，结合病原体负荷、免疫功能和精子特征的量化来表征疾病如何影响雄性生殖行为和生理以及雌性偏好。这项工作对亚致死、疾病介导的行为和生理效应对个体的作用产生了新的见解。除了在新的研究领域为研究员提供培训支持外，这项工作还涉及重要的外联工作，包括教学生团体参观自然历史博物馆，开发与研究相关的在线教育模块，以及指导不同的本科生。

This is an NSF Postdoctoral Research Fellowship in Biology, under the program Broadening Participation of Groups Under-represented in Biology. The fellow, Talisin Hammond, is conducting research and receiving training that increases the participation of groups underrepresented in biology, at the University of Pittsburgh, and is being mentored by Cori Richards-Zawicki (sponsoring scientist). This research explores how the reproductive behavior and physiology of multiple species of frogs is affected by chytridiomycosis, a fungal disease that has decimated many amphibian populations. In addition to improving our understanding of how this disease impacts amphibians, which are currently highly threatened by numerous environmental factors, this work also clarifies the role of sub-lethal effects of disease on population dynamics and evolutionary processes. As part of this project the fellow is working with a natural history museum to teach student groups about science using sketch-noting. The fellow is also designing a research-based educational module, which will be freely available, and is working with an online network to find educators interested in its implementation. Finally, the fellow is mentoring diverse undergraduate students.Wildlife diseases impact populations both directly, through mortality, and indirectly, through sub-lethal changes to host biology. Disease-induced fatalities can be devastating, but sub-lethal changes in behavior and physiology also have the potential to exert substantial pressure on populations. The terminal investment hypothesis, which states that animals with decreasing future reproductive potential should invest more in immediate reproduction, predicts that sick animals with decreased longevity should elevate reproductive effort, and that species with higher susceptibility should increase effort more. The fellow's research is testing this hypothesis, focusing on chytridiomycosis as the disease agent. The processes by which this disease kills amphibians are better-understood than its sub-lethal impacts, and few studies have experimentally described how chytridiomycosis impacts reproductive behavior and physiology. This project uses three congeneric frog species with differing disease susceptibility, using call recordings, behavioral choice tests, and hormonal manipulations in conjunction with quantifications of pathogen load, immune function and spermatic traits to characterize how the disease affects male reproductive behavior and physiology, and female preference. This work is generating novel insights into the role of sub-lethal, disease-mediated behavioral and physiological effects on individuals. In addition to providing training support for the fellow in a new field of study, this work also involves significant outreach, including teaching student groups visiting natural history museums, developing a research-related, online-available educational module, and mentoring diverse undergraduate students.