Brodie Edmund D, Brodie Edmund D
Department of Biology, Indiana University, Bloomington, Indiana, 47405.
Department of Biology, Utah State University, Logan, Utah, 84322-5305.
Evolution. 1999 Apr;53(2):626-631. doi: 10.1111/j.1558-5646.1999.tb03798.x.
Evolutionary trade-offs often are expected to arise between traits that share similar functions or resources. Such costs are well known from a variety of coevolutionary systems, but examples are conspicuously absent from predator-prey interactions. We present evidence of a trade-off between two disparate functions-predatory and anti-predatory ability-in a species of garter snake that has evolved resistance to the neurotoxin of its prey. Patterns of among-family variation suggest a genetic basis to the trade-off. Both resistant and nonresistant populations of snakes exhibit the trade-off, suggesting that it stems from a fundamental aspect of organismal performance. This cost may help to explain the geographic mosaic of predator exploitative ability and prey defense that exists in this system.
进化权衡通常预计会出现在具有相似功能或资源的性状之间。这种代价在各种协同进化系统中是众所周知的，但在捕食者与猎物的相互作用中却明显缺乏相关例子。我们提供了一种束带蛇的证据，表明在两种不同的功能——捕食能力和反捕食能力之间存在权衡，这种束带蛇已经进化出对其猎物神经毒素的抗性。家系间变异模式表明这种权衡具有遗传基础。抗性和非抗性蛇种群都表现出这种权衡，这表明它源于生物体表现的一个基本方面。这种代价可能有助于解释该系统中存在的捕食者利用能力和猎物防御的地理镶嵌现象。
