Collaborative Research: The Effects of Hostplant Chemistry and Invertebrate Predators on Caterpillar Foraging and Hostplant Fitness

影响植食昆虫觅食方式的两个主要因素是寄主植物化学和天敌。然而，寄主植物化学和捕食在决定昆虫食草动物觅食模式中的相对重要性以及这些因素相互作用的程度在很大程度上是未知的。利用平原植物环烯醚萜苷系统，寄主植物防御化学的表达范围将通过先前已被化学表征的克隆基因型来控制。在一个实验花园里，研究人员将评估两种毛毛虫的觅食模式，一种是专门的，一种是通用的，在两种不同的无脊椎食肉动物黄蜂和臭虫的存在和缺席的情况下。同时测定寄主植物相应的环烯醚萜和营养化学成分，以及幼虫的环烯醚萜化学成分和生长速率。此外，植物适应性由于草食动物的捕食者的存在和不存在将被检查。研究结果将表明寄主植物化学和捕食者在确定两种典型毛虫觅食模式的生态学及其对食草动物寄主植物的影响方面的相对重要性。

Two of the major factors that affect the foraging patterns of insect herbivores are hostplant chemistry and natural enemies. However, the relative importance of hostplant chemistry and predation in determining foraging patterns of insect herbivores and the degree to which these factors interact are largely unknown. The range of expression of hostplant defensive chemistry, using a system of iridoid glycosides in plaintain, will be controlled using cloned genotypes that have been previously characterized chemically. In an experimental garden, the foraging patterns of two caterpillar species, a specialist and a generalist, in the absence and presence of two different kinds of invertebrate predators, wasps and stinkbugs, will be assessed. Concurrently, the corresponding iridoid and nutritional chemistry of the hostplant , and the iridoid chemistry and growth rate of the caterpillars will be determined. In addition, plant fitness due to the presence and absence of the herbivores' predators will be examined. The results will indicate the relative importance of hostplant chemistry and predators in determining the ecology of foraging patterns of two representative caterpillar species and the ensuing effects on the herbivores' hostplant.