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

蝾螈河豚毒素水平的变化模式：评估捕食者-猎物协同进化的潜力捕食者和猎物之间的军备竞赛协同进化的证据将在有毒蝾螈和它们的抗性蛇捕食者之间的独特自然相互作用中进行评估。蝾螈体内有一种毒性很强的神经毒素河豚毒素（TTX），可以阻断神经和肌肉中的钠离子通道。没有已知的捕食者可以摄入TTX并生存下来，除了一种独特的束带蛇，Thamnophis sirtalis。以前的工作表明，这种捕食者的种群对TTX的抗性各不相同，并且存在进化增加抗性的潜力。 为了确定蝾螈防御是否与共同进化理论预测的捕食者利用能力模式相匹配，将使用高效液相色谱法（HPLC）来测定蝾螈种群内和种群间的毒素水平。 这种方法将确定蝾螈是否存在必要的个体、遗传和种群变异来进化以应对捕食者，也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相一致。共同进化，即一个物种为回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。 虽然协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-猎物相互作用可能有所不同。目前的研究将是第一个和最完整的研究捕食者和猎物之间的共同进化。 此外，这项研究将揭示一个重要的神经毒素，TTX，这是广泛用于神经功能和发育研究的自然变异，通过确定猎物的TTX的来源和捕食者的TTX抗性机制。

Patterns of Variation in Newt Tetrodotoxin Levels: Evaluating the Potential for Predator-Prey CoevolutionEvidence 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 matched 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 an important neurotoxin, TTX, which is 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.