Disease Ecology and its Role in Shaping Life History

该研究旨在调查疾病如何在亚利桑那州的蝾螈种群中出现，在种群中的个体之间传播，在一个地区的种群中传播，并最终通过自然选择改变蝾螈的生活史。将测试三个假设。在栖息地内，动物、土壤或水域的病毒和环境变化通过刺激病原体生长或削弱宿主蝾螈而引发感染。或者，在一个栖息地的蝾螈是易感的，疾病是从其他地方引入的。实验和实地观察将评估蝾螈、无脊椎动物、牛、鸟类或人类作为可能的疾病宿主或传播病毒的媒介的作用。最后，疾病选择对抗同类相食，解释了蝾螈生活史的区域差异。病毒-载体-虎蝾螈系统是检验疾病生态学模型的理想方法。亚利桑那州的种群得到了充分的研究，主要的病毒病原体是已知的，感染是频繁的，一个濒临灭绝的亚种的所有栖息地都可以在疾病常见的地方取样。在过去的15年里，一些两栖动物物种的数量稳步下降，甚至灭绝，病原体是一个可能的原因。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重要例子。拟议的实验和观察包括生态学，进化论，病理学，病毒学和分子遗传学专家。垂直整合的现场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.