Pesticide tolerance in amphibians: induced tolerance in susceptible populations, constitutive tolerance in tolerant populations

The role of plasticity in shaping adaptations is important to understanding the expression of traits within individuals and the evolution of populations. With increasing human impacts on the environment, one challenge is to consider how plasticity shapes responses to anthropogenic stressors such as contaminants. To our knowledge, only one study (using mosquitoes) has considered the possibility of induced insecticide tolerance. Using populations of wood frogs (Lithobates sylvaticus) located close to and far from agricultural fields, we discovered that exposing some populations of embryos and hatchlings to sublethal concentrations of the insecticide carbaryl induced higher tolerance to a subsequent lethal concentration later in life. Interestingly, the inducible populations were located >800 m from agricultural areas and were the most susceptible to the insecticide. In contrast, the noninducible populations were located close to agricultural areas and were the least susceptible. We als...表型可塑性（plasticity）在塑造生物适应性过程中的作用，对于解析个体内性状的表达模式以及种群的演化进程均具有重要意义。随着人类活动对环境的影响日益加剧，当前一项核心研究挑战在于厘清表型可塑性如何调控生物对人为胁迫因子（anthropogenic stressors）的响应，例如各类环境污染物。据我们所知，目前仅有一项以蚊子为研究对象的研究探讨了诱导型杀虫剂耐受性（induced insecticide tolerance）的可能性。本研究以距农田远近不同的美洲林蛙（Lithobates sylvaticus）种群为实验材料，将部分种群的胚胎及幼体暴露于杀虫剂甲萘威（carbaryl）的亚致死浓度环境中，结果发现此类个体在后续生命阶段，对该杀虫剂的致死浓度表现出更高的耐受性。值得注意的是，具备诱导耐受性的种群均距农田超过800米，且对该杀虫剂最为敏感；与之相反，无诱导耐受性的种群均紧邻农田分布，且对该杀虫剂的敏感性最低。本研究还