Jacquier Lauren, Molet Mathieu, Bocquet Céline, Doums Claudie
Institute of Ecology and Environmental Sciences of Paris (IEES-Paris), UPEC, CNRS, Sorbonne Université, IRD, INRA, 75005 Paris, France.
Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE-PSL, Université des Antilles, 75005 Paris, France.
Animals (Basel). 2021 Apr 8;11(4):1050. doi: 10.3390/ani11041050.
Trace metals such as cadmium are found in high concentrations in urban environments. Animal and plant populations living in heavily contaminated environments could adapt to trace metals exposure. A recent study shows that urban populations of the acorn ant are more resistant to cadmium than their forest counterparts. However, this study was performed using field colonies that had just come out of hibernation. Because urban and forest hibernation environments differ, the differential resistance to trace metals may originate either from differential hibernation conditions or from a different resistance baseline to cadmium. In this study, we tested these two hypotheses using laboratory common garden hibernation conditions. We let urban and forest colonies of the ant hibernate under the same laboratory conditions for four months. After this hibernation period, we also collected field-hibernating colonies and we compared cadmium resistance between urban and forest colonies depending on the hibernation condition. We found a differential response to cadmium under common garden, with urban colonies displaying less larval mortality and lower size reduction of the produced individuals. This suggests a different resistance baseline of urban colonies to cadmium. However, unexpectedly, we did not detect the differential response between urban and forest colonies in the field, suggesting a more complex scenario involving both genetic and environmental influences.
镉等痕量金属在城市环境中含量很高。生活在重度污染环境中的动植物种群可能会适应痕量金属暴露。最近的一项研究表明，橡实蚁的城市种群比其森林中的同类对镉更具抗性。然而，这项研究是使用刚从冬眠中苏醒的野外蚁群进行的。由于城市和森林的冬眠环境不同，对痕量金属的不同抗性可能源于不同的冬眠条件，也可能源于对镉的不同抗性基线。在本研究中，我们使用实验室共同花园冬眠条件来检验这两个假设。我们让城市和森林的蚁群在相同的实验室条件下冬眠四个月。在这个冬眠期之后，我们还收集了野外冬眠的蚁群，并根据冬眠条件比较了城市和森林蚁群对镉的抗性。我们发现在共同花园条件下对镉有不同的反应，城市蚁群的幼虫死亡率较低，所产生个体的体型减小幅度也较小。这表明城市蚁群对镉有不同的抗性基线。然而，出乎意料的是，我们在野外没有检测到城市和森林蚁群之间的差异反应，这表明存在一个涉及遗传和环境影响的更复杂的情况。
