Disease Ecology and its Role in Shaping Life History

这项拟议的研究调查了疾病如何在亚利桑那州的火蜥蜴种群中出现，在种群中的个体之间传播，在一个地区的种群中传播，最后通过自然选择可能改变火蜥蜴的生活史。三个假说将被检验。在栖息地内，动物、土壤或水中藏有病毒，环境变化通过刺激病原体生长或削弱宿主火蜥蜴而引发感染。或者，栖息地的火蜥蜴很容易受到感染，疾病会从其他地方传播。实验和实地观察将评估火蜥蜴、无脊椎动物、奶牛、鸟类或人类作为可能的疾病宿主或传播病毒的媒介所起的作用。最后，疾病选择了防止食人，这解释了火蜥蜴生活史上的区域差异。病毒-媒介-老虎火蜥蜴系统是测试疾病生态学模型的理想选择。亚利桑那州的种群经过了充分的研究，主要的病毒病原体已知，感染频繁，并且可以对疾病常见的一个濒危亚种的所有栖息地进行采样。在过去的15年里，一些两栖动物物种一直在稳步下降，甚至灭绝，病原体可能是原因之一。这项研究将促进我们对病原体作为两栖动物衰退的一个因素的理解；这是生物多样性普遍丧失的一个关键例子。拟议的实验和观察纳入了生态学、进化论、病理学、病毒学和分子遗传学的专家。垂直整合的野外和实验室实验将解开从分子遗传学到种群生物学的复杂相互作用，以测试疾病生态学的一般模型。

ABSTRACT The proposed research investigates how disease emerges in populations of salamanders in Arizona, is transmitted among individuals in populations, spreads across populations in a region, and finally, via natural selection, may alter salamander life history. Three hypotheses will be tested. Within a habitat, animals, soil, or water harbor viruses and environmental changes initiate infections by stimulating pathogen growth or weakening host salamanders. Alternatively, salamanders in a habitat are susceptible and disease is introduced from elsewhere. Experiments and field observations will evaluate the roles of salamanders, invertebrates, cows, birds, or humans as possible reservoirs of disease or vectors dispersing virus. Finally, disease selects against cannibalism, accounting for regional variation in salamander life history. The virus-vector-tiger salamander system is ideal for testing models in disease ecology. Arizona populations are well-studied, the principal viral pathogen is known, infections are frequent, and all habitats for one endangered subspecies where disease is common can be sampled. In the last fifteen years some species of amphibians have declined steadily, even to extinction, and pathogens are a possible cause. This research will advance our understanding of pathogens as a factor in amphibian declines; a key example of the general loss of biodiversity. Proposed experiments and observations incorporate experts in ecology, evolution, pathology, virology, and molecular genetics. Vertically-integrated field and laboratory experiments will untangle complex interactions from molecular genetics to population biology to test general models of disease ecology.