Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, 46556, USA.
Darrin Fresh Water Institute, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, 12180, USA.
Ecol Appl. 2021 Jun;31(4):e02305. doi: 10.1002/eap.2305. Epub 2021 Mar 28.
Exposure to agrochemicals can drive rapid phenotypic and genetic changes in exposed populations. For instance, amphibian populations living far from agriculture (a proxy for agrochemical exposure) exhibit low pesticide tolerance, but they can be induced to possess high tolerance following a sublethal pesticide exposure. In contrast, amphibian populations close to agriculture exhibit high, constitutive tolerance to pesticides. A recent study has demonstrated that induced pesticide tolerance appears to have arisen from plastic responses to predator cues. As a result, we might expect that selection for constitutive pesticide tolerance in populations near agriculture (i.e., genetic assimilation) will lead to the evolution of constitutive responses to natural stressors. Using 15 wood frog (Rana sylvatica) populations from across an agricultural gradient, we conducted an outdoor mesocosm experiment to examine morphological (mass, body length, and tail depth) and behavioral responses (number of tadpoles observed and overall activity) of tadpoles exposed to three stressor environments (no-stressor, competitors, or predator cues). We discovered widespread differences in tadpole traits among populations and stressor environments, but no population-by-environment interaction. Subsequent linear models revealed that population distance to agriculture (DTA) was occasionally correlated with tadpole traits in a given environment and with magnitudes of plasticity, but none of the correlations were significant after Bonferroni adjustment. The magnitudes of predator and competitor plasticity were never correlated with the magnitude of pesticide-induced plasticity that we documented in a companion study. These results suggest that while predator-induced plasticity appears to have laid the foundation for the evolution of pesticide-induced plasticity and its subsequent genetic assimilation, inspection of population-level differences in plastic responses show that the evolution of pesticide-induced plasticity has not had a reciprocal effect on the evolved plastic responses to natural stressors.
接触农用化学品会导致暴露种群发生快速的表型和遗传变化。例如，远离农业的（农用化学品暴露的替代指标）生活的两栖动物种群对农药的耐受性较低，但在亚致死农药暴露后，它们可以被诱导具有高耐受性。相比之下，靠近农业的两栖动物种群对农药具有高的、组成型的耐受性。最近的一项研究表明，诱导的农药耐受性似乎是由于对捕食者线索的可塑性反应而产生的。因此，我们可能会预期，在靠近农业的种群中对组成型农药耐受性的选择（即遗传同化）将导致对自然胁迫的组成型反应的进化。使用来自农业梯度的 15 个林蛙（Rana sylvatica）种群，我们进行了一项户外中观实验，以研究暴露于三种胁迫环境（无胁迫、竞争者或捕食者线索）的蝌蚪的形态（质量、体长和尾巴深度）和行为反应（观察到的蝌蚪数量和整体活动）。我们发现，种群间和胁迫环境中蝌蚪特征存在广泛差异，但没有种群与环境的相互作用。随后的线性模型表明，与农业的种群距离（DTA）偶尔与特定环境中的蝌蚪特征以及可塑性幅度相关，但在 Bonferroni 调整后，没有相关性具有统计学意义。捕食者和竞争者可塑性的幅度从未与我们在同伴研究中记录的农药诱导可塑性的幅度相关。这些结果表明，虽然捕食者诱导的可塑性似乎为农药诱导的可塑性及其随后的遗传同化奠定了基础，但对群体水平的可塑性反应差异的检查表明，农药诱导的可塑性的进化对自然胁迫的进化的可塑性反应没有产生相互作用。
