Janssens Lizanne, Tüzün Nedim, Stoks Robby
Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Charles Deberiotstraat 32, B-3000 Leuven, Belgium.
Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Charles Deberiotstraat 32, B-3000 Leuven, Belgium.
Environ Pollut. 2017 Nov;230:351-359. doi: 10.1016/j.envpol.2017.06.082. Epub 2017 Jun 29.
Under global change organisms are exposed to multiple, potentially interacting stressors. Especially interactions between successive stressors are poorly understood and recently suggested to depend on their timing of exposure. We particularly need studies assessing the impact of exposure to relevant stressors at various life stages and how these interact. We investigated the single and combined impacts of a heat wave (mild [25 °C] and extreme [30 °C]) during the egg stage, followed by successive exposure to esfenvalerate (ESF) and a heat wave during the larval stage in damselflies. Each stressor caused mortality. The egg heat wave and larval ESF exposure had delayed effects on survival, growth and lipid peroxidation (MDA). This resulted in deviations from the prediction that stressors separated by a long time interval would not interact: the egg heat wave modulated the interaction between the stressors in the larval stage. Firstly, ESF caused delayed mortality only in larvae that had been exposed to the extreme egg heat wave and this strongly depended upon the larval heat wave treatment. Secondly, ESF only increased MDA in larvae not exposed to the egg heat wave. We found little support for the prediction that when there is limited time between stressors, synergistic interactions should occur. The intermediate ESF concentration only caused delayed mortality when combined with the larval heat wave, and the lowest ESF concentrations only increased oxidative damage when followed by the mild larval heat wave. Survival selection mitigated the interaction patterns between successive stressors that are individually lethal, and therefore should be included in a predictive framework for the time-scale dependence of the outcome of multistressor studies with pollutants. The egg heat wave shaping the interaction pattern between successive pesticide exposure and a larval heat wave highlights the connectivity between the concepts of 'heat-induced pesticide sensitivity' and 'pesticide-induced heat sensitivity'.
在全球变化的背景下，生物体会面临多种可能相互作用的压力源。尤其是连续压力源之间的相互作用，目前人们对此了解甚少，最近有研究表明这种相互作用取决于压力源的暴露时间。我们尤其需要开展研究，评估在不同生命阶段暴露于相关压力源的影响以及这些压力源之间是如何相互作用的。我们研究了豆娘在卵期遭受热浪（轻度[25℃]和极端[30℃]），随后在幼虫期连续暴露于氰戊菊酯（ESF）和热浪的单一及联合影响。每个压力源都会导致死亡。卵期热浪和幼虫期ESF暴露对生存、生长和脂质过氧化（丙二醛）产生了延迟影响。这导致与长期间隔分开的压力源不会相互作用这一预测出现偏差：卵期热浪调节了幼虫期压力源之间的相互作用。首先，ESF仅在暴露于极端卵期热浪的幼虫中导致延迟死亡，而且这在很大程度上取决于幼虫期的热浪处理。其次，ESF仅在未暴露于卵期热浪的幼虫中增加了丙二醛含量。对于压力源之间时间间隔有限时应发生协同相互作用这一预测，我们几乎没有找到支持证据。中等浓度的ESF仅在与幼虫期热浪联合时导致延迟死亡，而最低浓度的ESF仅在随后出现轻度幼虫期热浪时增加氧化损伤。生存选择减轻了连续压力源之间单独致命的相互作用模式，因此应将其纳入多压力源污染物研究结果时间尺度依赖性的预测框架中。卵期热浪塑造了连续农药暴露和幼虫期热浪之间的相互作用模式，突出了“热诱导农药敏感性”和“农药诱导热敏感性”概念之间的联系。
