Aquatic media are ultimate recipients of various contaminants including pesticides pervasively applied in agrosystems. Characterizing the ecotoxicity of pesticides and their mixtures to aquatic wildlife at field-realistic levels is thus crucial for environmental risk assessment. This study aims at assessing the effects of two current-use insecticides, imidacloprid and chlorpyrifos, on Gammarus fossarum using multi-level biomarkers. In microcosms, gammarids were exposed for 72 h to insecticides tested individually or in mixture at 0.01, 0.1 and 1 μg/L of each chemical. Multi-metric responses were assessed at the individual level (behavioural traits: locomotion, respiration and amplexus formation) and the cellular level (enzymes involved in growth, moulting, digestion and cell stress). The results showed insecticide-elicited behavioural and biochemical responses from the lowest concentration of 0.01 μg/L. Overall, single exposures stimulated behavioural traits and inhibited enzymatic activities, highlighting subtle impacts at different organizational levels but these were not dose related. For binary mixtures, antagonistic effects (i.e. less-than-additive) on biomarkers were mainly observed when compared with single exposures. Multi-variable analyses indicated the complementarity of behavioural and biochemical biomarkers in identifying sublethal biological alterations and dose-dependent multiple action sites of insecticides. Besides, the mortality observed only for the mixture at 1 μg/L demonstrated a high lethal potential of insecticides in a simple binary combination. To conclude, this study demonstrates disturbances in individual performances and cellular impairments occurring at environmentally realistic exposure levels in a non-target wild species. Since the sublethal effects, such as those identified with this multi-biomarker approach, could lead to long-term alterations in population dynamics of agricultural areas, they constitute promising early endpoints for risk assessment of insecticides.

中文翻译：

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杀虫剂对暴露于环境中实际水平的非目标两栖类斜纹夜蛾的多水平生物标志物的单一或联合作用。

水生介质是各种污染物的最终接受者，包括在农业系统中普遍使用的农药。因此，在野外实际水平上表征农药及其混合物对水生野生生物的生态毒性对于环境风险评估至关重要。这项研究旨在使用多级生物标记物评估两种目前使用的杀虫剂吡虫啉和毒死rif对镰刀菌的影响。在微观世界中，将γ-杀菌剂暴露于单独测试或以每种化合物0.01、0.1和1μg/ L的混合物测试的杀虫剂72小时。在个体水平（行为特征：运动，呼吸和丛状形成）和细胞水平（参与生长，蜕皮，消化和细胞应激的酶）评估多指标反应。结果表明，最低浓度为0.01μg/ L时，杀虫剂会引起行为和生化反应。总体而言，单次接触刺激了行为特征并抑制了酶的活性，突显了在不同组织水平上的细微影响，但这些与剂量无关。对于二元混合物，与单次接触相比，主要观察到对生物标志物的拮抗作用（即，小于相加作用）。多变量分析表明，行为和生化生物标志物在鉴定杀虫剂的亚致死性生物学改变和剂量依赖性多重作用位点方面具有互补性。此外，仅以1μg/ L的混合物观察到的死亡率显示了简单的二元组合形式的杀虫剂具有很高的致死潜力。总而言之，这项研究表明，在非目标野生物种中，在环境实际暴露水平下，个体行为受到干扰，细胞受损。由于亚致死效应，例如用这种多生物标志物方法鉴定的，可能导致农业地区种群动态的长期变化，因此它们构成了杀虫剂风险评估的有希望的早期终点。