Collaborative Research: Patterns of Variation in Newt Tetrodotoxin Levels -- Evaluating the Potential for Predator-Prey Coevolution

Brodie，III.9903829捕食者和被捕食者之间军备竞赛的共同进化证据将在有毒蝾螈和它们抵抗蛇的捕食者之间独特的自然相互作用中进行评估。蝾螈拥有强大的神经毒素河豚毒素(TTX)，它可以阻断神经和肌肉中的钠通道。已知的捕食者中没有一种能够摄取TTX并存活下来，除了一种吊袜蛇，Thamnopits sirtalis。以前的工作已经证明，这种捕食者的种群对TTX的抵抗力各不相同，并且存在进化出更强抵抗力的潜力。为了确定是否与共同进化理论预测的捕食者利用能力的模式相匹配，将使用高效液相色谱(HPLC)来检测种群内和种群之间的毒素水平。这一方法将确定是否存在必要的个体、遗传和种群变异，以应对捕食者的进化，并将评估观察到的匹配模式是否与共同进化的“军备竞赛”观点一致。了解推动共同进化的物种之间的相互作用是进化生物学的主要目标。共同进化是指一个物种因应另一个物种而进化，被认为是生物多样性的主要引擎之一。虽然共同进化被认为是许多生态相互作用的共同结果，但有强有力的理论和经验理由怀疑捕食者和猎物的相互作用可能是不同的。目前的研究将是关于捕食者和猎物之间共同进化的最早和最完整的研究之一。此外，这项研究还将通过确定猎物中TTX的来源和捕食者对TTX的抗性机制，揭示TTX的自然变异。TTX是一种重要的神经毒素，广泛应用于神经功能和发育的研究。

Brodie, III.9903829Evidence for arms race coevolution between predator and prey will be evaluated in a unique natural interaction between toxic newts and their resistant snake predators. Newts possess the potent neurotoxin tetrodotoxin (TTX), which blocks sodium channels in nerves and muscles. No known predator can ingest TTX and survive except for a single species of garter snake, Thamnophis sirtalis. Previous work has demonstrated that populations of this predator vary in their resistance to TTX, and that the potential to evolve increased resistance is present. To determine if newt defenses match patterns of predator exploitative ability as predicted by coevolutionary theory, High Performance Liquid Chromatography (HPLC) will be used to assay levels of toxin within and among populations of newts. This approach will determine if the requisite individual, genetic and population variation exists for newts to evolve in response to predators, and will also evaluate whether observed patterns of matching are consistent with an "arms race" view of coevolution.Understanding the interactions between species that drive coevolution is a major goal of evolutionary biology. Coevolution, in which one species evolves in response to another species, is thought to be one of the major engines of biodiversity. Although coevolution is thought to be a common outcome of many ecological interactions, there are strong theoretical and empirical reasons to suspect that predator-prey interaction may be different. The current study will represent one of the first and most complete studies of coevolution among predator and prey. Additionally, this research will shed important light on natural variation in TTX, an important neurotoxin used widely in studies of nerve function and development, by identifying the sources of TTX in prey and the mechanism of TTX resistance in predators.