Dissertation Research: Differential Selection in Different Environments in a Polyphagous Herbivore

虎燕尾使用多种化学成分不同的植物。这些寄主物种对产卵雌性的吸引力和对毛虫生长的适宜性各不相同。此外，基因不同的个体对同一寄主植物表现出不同的反应。潜在地，燕尾识别不同植物或在不同植物上生长的不同能力有助于维持在自然燕尾种群中观察到的大部分遗传变异。虽然选择倾向于消除某些宿主上的某些基因型，但它倾向于增加它们在其他宿主上的频率。本研究旨在探讨虎燕尾利用寄主植物的生理和行为模式的遗传基础。研究人员假设这个亚种是由不同适应基因型和种群的复杂组成的。实验将比较三个地理种群和种群内的科对三种不同寄主植物的反应。互补分析将确定这些群体的遗传亚结构。从这些实验室和实地研究中获得的信息将阐明宿主多样性在维持单一物种种群之间和种群内部的遗传变异性方面的作用。这些知识将有助于了解昆虫如何适应它们的食物来源，并将证明对制定重要商业作物品种的病虫害管理计划是有用的。

Tiger swallowtails use a number of plant species that vary in their chemical composition. These host species differ in their attractiveness to egg-laying females and their suitability for caterpillar growth. In addition, genetically different individuals show dissimilar responses on identical host plants. Potentially, the differential ability of swallowtails to recognize or grow on different plant species serves to maintain much of the genetic variation observed in natural swallowtail populations. Although selection tends to eliminate certain genotypes on certain hosts, it tends to increase their frequency on other hosts. The proposed research is designed to assess the genetic basis for the physiological and behavioral patterns of host plant usage by the tiger swallowtail. The investigators hypothesize that this subspecies is comprised of a complex of differentially adapted genotypes and populations. Experiments will compare the responses of three geographic populations and families within populations on three different host plants. Complementary analyses will determine the genetic substructure of these populations. Information obtained from these laboratory and field studies will elucidate the role of host diversity in maintaining genetic variability among and within populations of a single species. Such knowledge will help in understanding how insects adapt to their food sources and will prove useful in developing pest management programs for commercially important crop species.