The Evolvability of Chemical Sequestration in an Insect Herbivore: Tradeoffs in a Triptrophic Interaction

许多植食性昆虫(食草动物)使用从植物中获取(隔离)的毒素来进行化学防御。然而，这种防御可能是一件太好的事情，如果它们强加了代价，比如生长速度降低或后代减少。本研究以管状燕尾蝶为模型系统，考察了封存的演化过程。燕尾草是难吃的，因为它们的毛虫将有毒的生物碱(马兜铃酸)从它们的管状寄主植物中隔离出来。育种实验将评估用于封存的遗传变异。自然选择应该缓和被隔离的数量，以最大限度地增加防御效益，最大限度地减少成本。田间和实验室实验将通过饲料化学操作和选择性繁殖隔离能力来解决这些成本/收益。从化学鸡尾酒中隔离的能力，特别是管状物种，可以促进蝴蝶种群的分化。用不同的管状植物进行蝴蝶种群的实验室杂交将评估当地适应的程度。这项研究将加深我们对植物化学如何指导食草动物进化的理解。这项研究将为本科生和研究生提供实验和分析化学方面的培训，并将为初中和高中科学教育工作者提供实践科学经验。最后，这个项目将作为一个关于生态相互作用和进化的公共教育工具

Many plant-eating insects (herbivores) chemically defend themselves using toxins obtained (sequestered) from plants. However, such defenses can be too much of a good thing if they impose a cost, such as reduced growth rate or fewer offspring. This study examines the evolution of sequestration, using the pipevine swallowtail butterfly as a model system. Pipevine swallowtails are unpalatable because their caterpillars sequester toxic alkaloids (aristolochic acids) from their pipevine host plants. Breeding experiments will assess genetic variation for sequestration. Natural selection should temper the amount sequestered to maximize defensive benefits and minimize costs. Field and laboratory experiments will address these costs / benefits through diet chemistry manipulation and selective breeding for sequestration ability. The ability to sequester from the chemical cocktail present in particular pipevine species could facilitate differentiation of butterfly populations. Laboratory crossbreeding of butterfly populations using different pipevine species will assess the extent of local adaptation.This study will enhance our understanding of how plant chemistry directs herbivore evolution. This research will provide training in experimentation and analytical chemistry for undergraduate and graduate students, and will involve hands-on scientific experience for middle and high school science educators. Finally, this project will serve as a vehicle for public education about ecological interactions and evolution