Op de Beeck Lin, Verheyen Julie, 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 May;224:714-721. doi: 10.1016/j.envpol.2016.11.014. Epub 2016 Dec 28.
Global warming and chemical pollution are key anthropogenic stressors with the potential to interact. While warming can change the impact of pollutants and pollutants can change the sensitivity to warming, both interaction pathways have never been integrated in a single experiment. Therefore, we tested the effects of warming and multiple pesticide pulses (allowing accumulation) of chlorpyrifos on upper thermal tolerance (CTmax) and associated physiological traits related to aerobic/anaerobic energy production in the damselfly Ischnura elegans. To also assess the role of latitude-specific thermal adaptation in shaping the impact of warming and pesticide exposure on thermal tolerance, we exposed larvae from replicated high- and low-latitude populations to the pesticide in a common garden rearing experiment at 20 and 24 °C, the mean summer water temperatures at high and low latitudes. As expected, exposure to chlorpyrifos resulted in a lower CTmax. Yet, this pesticide effect on CTmax was lower at 24 °C compared to 20 °C because of a lower accumulation of chlorpyrifos in the medium at 24 °C. The effects on CTmax could partly be explained by reduction of the aerobic scope. Given that these effects did not differ between latitudes, gradual thermal evolution is not expected to counteract the negative effect of the pesticide on thermal tolerance. By for the first time integrating both interaction pathways we were not only able to provide support for both of them, but more importantly demonstrate that they can directly affect each other. Indeed, the warming-induced reduction in pesticide impact generated a lower pesticide-induced climate change sensitivity (in terms of decreased upper thermal tolerance). Our results indicate that, assuming no increase in pesticide input, global warming might reduce the negative effect of multiple pulse exposures to pesticides on sensitivity to elevated temperatures.
全球变暖和化学污染是具有潜在相互作用可能性的关键人为压力源。虽然变暖会改变污染物的影响，污染物也会改变对变暖的敏感性，但这两种相互作用途径从未在单一实验中整合过。因此，我们测试了变暖以及多次使用毒死蜱农药脉冲（允许积累）对豆娘（艾氏异痣蟌）的上限热耐受性（CTmax）以及与有氧/无氧能量产生相关的生理特征的影响。为了评估纬度特异性热适应在塑造变暖和农药暴露对热耐受性影响方面的作用，我们在一个共同花园饲养实验中，将来自高纬度和低纬度重复种群的幼虫在20℃和24℃（高纬度和低纬度夏季平均水温）下暴露于该农药。正如预期的那样，接触毒死蜱导致CTmax降低。然而，由于24℃时毒死蜱在介质中的积累量较低，与20℃相比，这种农药对CTmax的影响在24℃时较小。对CTmax的影响部分可以通过有氧范围的降低来解释。鉴于这些影响在不同纬度之间没有差异，预计渐进的热进化不会抵消农药对热耐受性的负面影响。通过首次整合这两种相互作用途径，我们不仅能够为两者提供支持，更重要的是证明它们可以直接相互影响。事实上，变暖导致的农药影响降低产生了较低的农药诱导的气候变化敏感性（就上限热耐受性降低而言）。我们的结果表明，假设农药投入不增加，全球变暖可能会降低多次脉冲暴露于农药对高温敏感性的负面影响。
