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）利用从植物中获取（隔离）的毒素进行化学防御。然而，如果这样的防御带来了代价，比如降低生长速度或减少后代，那么这种防御就可能是一件好事。本研究以管道燕尾蝶为模型系统，探讨了固存的演化过程。管藤燕尾是难吃的，因为它们的毛虫从它们的管藤宿主植物中吸收有毒的生物碱（马兜铃酸）。育种实验将评估用于封存的遗传变异。自然选择应该调节隔离的数量，使防御利益最大化，成本最小化。现场和实验室实验将通过饮食化学操纵和选择性育种来解决这些成本/效益问题。从存在于特定管道物种中的化学混合物中分离的能力可以促进蝴蝶种群的分化。使用不同管道物种的蝴蝶种群的实验室杂交将评估当地适应的程度。这项研究将增强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者提供实际的科学经验。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