Feeding ecology of outbreak insect species

田间和室内饲养试验的结果表明，香脂冷杉树叶中的总单宁组分似乎是寄主对云杉芽虫的抗性机制。然而，具体涉及的单宁和他们的个人模式的行动仍有待调查。我推测，特定的叶面单宁协同作用，影响幼虫的生存和生长，通过干扰幼虫的食物利用过程，这些特定的单宁有不同的模式对幼虫的行动。这一假设将使用重量分析，行为，电生理学和组织学研究的幼虫饲养人工饲料补充各种水平和组合的纯化学品提取的树叶。根据地方适应假说，在营养，防御，或物候特征的长寿植物种群内的空间异质性结构的短命的，专门的食草动物种群进入demes（遗传上不同的人口）适应个别主机的表型。 我假设，食物质量恶化（连续的昆虫落叶引起的宿主表型的变化）在爆发期间施加选择性压力，改变种群的基因频率，这反过来又导致更好地适应不良的饲养条件下的虫种群。在实验室条件下，使用滞育后的同胞和来自受损林分的新鲜树叶或来自未受损林分的树叶，在连续四代昆虫上进行相互转移实验。将记录云杉芽虫的生物学性能，并进行定量遗传分析。将使用高质量和低质量的饲料进行额外的实验室饲养实验，以调查几代营养胁迫对云杉芽虫的影响所涉及的过程。 我假设，通过选择压力，营养压力施加在云杉芽虫几代修改幼虫发育和食物利用，最佳营养平衡和积极和消极的食物质量变化（营养和二级化合物）的反应。

Results from field and laboratory rearing experiments indicate that total tannin fraction of balsam fir tree foliage appears to serve as mechanisms of host resistance to spruce budworm. However, the specific tannins involved and their individual mode of action remain to be investigated. I hypothesize that specific foliar tannins act synergically to influence larval survival and growth by interfering with larval food utilization processes and that these specific tannins have different modes of action on budworm larvae. This hypothesis will be tested using gravimetric, behavioral, electrophysiological, and histological studies on larvae reared on artificial diet supplemented with various levels and combinations of pure chemicals extracted from foliage. According to the local-adaptation hypothesis, the spatial heterogeneity in nutritive, defensive, or phenological traits within populations of long-lived plants structures populations of short-lived, specialized herbivores into demes (genetically different populations) adapted to the phenotypes of individual hosts. I hypothesize that food quality deterioration (change in host phenotype caused by successive insect defoliation) during an outbreak exerts a selective pressure on budworm population that changes gene frequency of the population which in turn leads to a better adaptation to poor feeding conditions. Reciprocal transfert experiments will be conducted over four successive generations of insect under laboratory conditions using postdiapausing siblings and fresh foliage from damaged stands or foliage from undamaged stands. Spruce budworm biological performances will be documented and quantitative genetic analysis performed. Additional laboratory rearing experiments will be conducted using high and low quality diets to investigate the processes involved in the impact of nutritional stress on spruce budworm over several generations. I hypothesize that, through selective pressure, nutritional stress imposed on spruce budworms over several generations modifies larval development and food utilization, optimal nutrient balance and responses to positive and negative food quality changes (nutrient and secondary compounds).