REU: The Interaction of Insect Herbivory, Environmental Stress, and Host Resistance

北亚利桑那州立大学的惠瑟姆博士将继续对生长在北亚利桑那日落陨石坑的灰烬和煤渣地里的小松进行研究。松树受到水分和养分的胁迫，尽管邻近的地点很少受到食草动物的影响，但受到胁迫的松树受到3种食草动物昆虫的攻击增加了许多倍。这种慢性和急性食草性导致了食草动物介导的树木性别变化，改变了树木的结构，大大降低了生长。将继续进行以下五个基本研究方向：实验操作压力和草食负荷来分离因果关系；2 .对抗性的化学和/或遗传基础进行量化；3 .量化昆虫食草对寄主根、冠和生殖系统的影响。4 .量化寄主抗性对草食动物存活和种子传播的影响；重建过去200年的慢性昆虫袭击。在6名研究人员的多学科技能下，通过昆虫转移实验、树木移植实验、补水施肥实验、植物初、次生生物化学、树木年代学和电泳等手段，对这些问题的研究取得了快速进展。由于遇到的极端环境条件，食草对这些植物的明显影响以及我们通过实验操纵主要成分的能力，该系统代表了一个整合植物-食草相互作用主要因素的模型。

Dr. Whitham of Northern Arizona State University will continue a study of pinyon pine, Pinus edulis, which grows on the ash and cinder fields of Northern Arizona's Sunset Crater. The pine is water and nutrient stressed, and although adjacent sites suffer little herbivory, stressed pinyons suffer many-fold increases in attack by 3 insect herbivores. This chronic and acute herbivory results in a herbivore-mediated sex change in the tree, altered tree architecture and greatly reduced growth. Five basic lines of research will be continued: 1. experimentally manipulate stress and herbivore loads to separate cause and effect, 2. quantify the chemical and/or genetic basis of resistance, 3. quantify the impacts of insect herbivory on the host's root, crown, and reproductive systems, 4. quantify the impacts of host resistance on herbivore survival and seed dispersal, and 5. reconstruct the past 200 years of chronic insect attack. With the multidisciplinary skills of 6 researchers, rapid progress has been made in examining these questions by employing insect transfer experiments, tree transplant experiments, supplemental water and fertilizing experiments, primary and secondary plant biochemistry, dendrochronology, and electrophoresis. Because of the extremes of environmental conditions encountered, the obvious impacts of herbivory on these plants and our ability to experimentally manipulate the major components, the system represents a model for integrating major factors in plant-herbivore interactions.