Department of Biological Sciences, College of the Environment and Life Sciences, University of Rhode Island, Kingston, Rhode Island.
Department of Biology, The Pennsylvania State University, University Park, Pennsylvania.
Glob Chang Biol. 2019 Feb;25(2):620-628. doi: 10.1111/gcb.14510. Epub 2018 Nov 29.
Understanding the processes driving formation and maintenance of latitudinal clines has become increasingly important in light of accelerating global change. Many studies have focused on the role of abiotic factors, especially temperature, in generating clines, but biotic factors, including the introduction of non-native species, may also drive clinal variation. We assessed the impact of invasion by predatory fire ants on latitudinal clines in multiple fitness-relevant traits-morphology, physiological stress responsiveness, and antipredator behavior-in a native fence lizard. In areas invaded by fire ants, a latitudinal cline in morphology is opposite both the cline found in museum specimens from historical populations across the species' full latitudinal range and that found in current populations uninvaded by fire ants. Similarly, clines in stress-relevant hormone response to a stressor and in antipredator behavior differ significantly between the portions of the fence lizard range invaded and uninvaded by fire ants. Changes in these traits within fire ant-invaded areas are adaptive and together support increased and more effective antipredator behavior that allows escape from attacks by this invasive predator. However, these changes may mismatch lizards to the environments under which they historically evolved. This research shows that novel biotic pressures can alter latitudinal clines in multiple traits within a single species on ecological timescales. As global change intensifies, a greater understanding of novel abiotic and biotic pressures and how affected organisms adapt to them across space and time will be central to predicting and managing our changing environment.
了解驱动纬度梯度形成和维持的过程，在全球变化加速的背景下变得越来越重要。许多研究集中在非生物因素（特别是温度）在产生梯度方面的作用，但生物因素，包括引入非本地物种，也可能驱动梯度变化。我们评估了捕食性红火蚁入侵对多个与适应度相关的特征——形态、生理应激反应和抗捕食者行为——在本地围栏蜥蜴中的纬度梯度的影响。在红火蚁入侵的地区，形态的纬度梯度与从物种全纬度范围的历史种群的博物馆标本中发现的梯度以及未被红火蚁入侵的当前种群中发现的梯度相反。同样，对胁迫源的应激相关激素反应和抗捕食者行为的梯度在红火蚁入侵和未入侵的围栏蜥蜴分布区之间也有显著差异。在红火蚁入侵地区，这些特征的变化是适应性的，共同支持了更强和更有效的抗捕食者行为，使蜥蜴能够逃避这种入侵捕食者的攻击。然而，这些变化可能使蜥蜴与它们历史上进化的环境不匹配。这项研究表明，新的生物压力可以在生态时间尺度内改变单个物种中多个特征的纬度梯度。随着全球变化的加剧，更深入地了解新的非生物和生物压力以及受影响的生物如何在空间和时间上适应它们，将是预测和管理我们不断变化的环境的核心。
