Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Charles Deberiotstraaat 32, B-3000 Leuven, Belgium; Institute of Aquaculture, Nha Trang University, No 2 Nguyen Dinh Chieu, Nha Trang, Vietnam.
Laboratory of Aquatic Ecology, Evolution and Conservation, University of Leuven, Charles Deberiotstraaat 32, B-3000 Leuven, Belgium.
Aquat Toxicol. 2014 Jul;152:215-21. doi: 10.1016/j.aquatox.2014.04.011. Epub 2014 Apr 19.
Recent insights indicate that negative effects of pesticides on aquatic biota occur at concentrations that current legislation considers environmentally protective. We here address two, potentially interacting, mechanisms that may contribute to the underestimation of the impact of sublethal pesticide effects in single species tests at room temperature: the impairment of predator and antipredator behaviours and the stronger impact of organophosphate pesticides at higher temperatures. To address these issues we assessed the effects of chlorpyrifos on the predator and antipredator behaviours of larvae of the damselfly Ischnura elegans, important intermediate predators in aquatic food webs, in a common-garden warming experiment with replicated low- and high-latitude populations along the latitudinal gradient of this species in Europe. Chlorpyrifos reduced the levels of predator behavioural endpoints, and this reduction was stronger at the higher temperature for head orientations and feeding strikes. Chlorpyrifos also impaired two key antipredator behavioural endpoints, activity reductions in response to predator cues were smaller in the presence of chlorpyrifos, and chlorpyrifos caused a lower escape swimming speed; these effects were independent of temperature. This suggests chlorpyrifos may impact food web interactions by changing predator-prey interactions both with higher (predators) and lower trophic levels (food). Given that only the interaction with the lower trophic level was more impaired at higher temperatures, the overall pesticide-induced changes in food web dynamics may be strongly temperature-dependent. These findings were consistent in damselflies from low- and high-latitude populations, illustrating that thermal adaptation will not mitigate the increased toxicity of pesticides at higher temperatures. Our study not only underscores the relevance of including temperature and prey-predator interactions in ecological risk assessment but also their potential interplay and thereby highlights the complexity of contaminant effects on predator-prey interactions being differentially temperature-dependent pending on the trophic level.
最近的研究结果表明，目前法律认为具有环保作用的农药浓度，对水生生物群体会产生负面影响。我们在这里讨论两个可能相互作用的机制，这些机制可能导致在室温下的单一物种测试中对亚致死农药效应的影响被低估：捕食者和反捕食者行为的损害，以及有机磷农药在较高温度下的影响更强。为了解决这些问题，我们评估了毒死蜱对蜻蜓幼虫的捕食者和反捕食者行为的影响，蜻蜓幼虫是水生食物网中重要的中间捕食者，这是一种在欧洲该物种的纬度梯度上进行的常见温室升温实验，包括具有代表性的低纬度和高纬度种群。毒死蜱降低了捕食行为终点的水平，而在较高温度下，头部定向和摄食攻击的减少更为明显。毒死蜱还损害了两个关键的反捕食行为终点，即对捕食者线索的反应减少，而在有毒死蜱的情况下，减少幅度较小，并且毒死蜱导致逃避游泳速度降低；这些影响与温度无关。这表明，毒死蜱可能通过改变捕食者-猎物相互作用，从而影响食物网的相互作用，包括较高（捕食者）和较低营养级（食物）。由于只有与较低营养级的相互作用在较高温度下受到更大的损害，因此食物网动态中整体农药诱导的变化可能强烈依赖于温度。这些发现与来自低纬度和高纬度种群的蜻蜓一致，这表明热适应不会减轻高温下农药毒性的增加。我们的研究不仅强调了在生态风险评估中包括温度和猎物-捕食者相互作用的相关性，还强调了它们的潜在相互作用，从而突出了污染物对捕食者-猎物相互作用的影响的复杂性，这些影响取决于温度，取决于营养级。
