Abstract：
Pesticide residue and thermal stress resulting from global climate change are parallel stressors for soil fauna. However, it remains ambiguous how elevated temperatures and pesticides can interact to threaten soil fauna. In the study, the acute and chronic clothianidin (CTD) toxicity to earthworms (Eisenia fetida) at different temperatures, and the effect of increasing temperature on antioxidant defense mechanisms in response to CTD were investigated. The acute toxicity of CTD was exacerbated by increased temperature in both filter paper contact tests (a decrease in the 48-h median lethal concentration (LC50) from 0.077 μg/cm2 at 20 °C to 0.009 μg/cm2 at 30 °C) and natural soil tests (a decrease in the 48-h LC50 from 0.774 mg/kg at 20 °C to 0.199 mg/kg at 30 °C). Exposure to CTD or high temperature (30 °C) triggered reactive oxygen species (ROS) overgeneration and increased antioxidant enzyme activities in earthworms; and the effect was particularly pronounced after exposure to both higher temperatures and CTD. At 20 and 25 °C, there was no significant change in the growth and reproduction of E. fetida after 56-d exposure to CTD-contaminated soil. However, the combined effect of CTD and high temperature (30 °C) significantly reduced the weight change rate, cocoon number, hatching rate, and number of juveniles on day 56. These results indicated that elevated temperature could aggravate acute and chronic CTD toxicity to earthworms. The findings emphasize that evaluating changes in pesticide toxicity under global warming is worth further investigation.
摘要：
全球气候变化导致的农药残留和热应力是土壤动物的平行压力源。然而,高温和农药如何相互作用威胁土壤动物仍然不明确。在研究中,不同温度下CTD对蚯蚓的急性和慢性毒性，研究了温度升高对CTD反应的抗氧化防御机制的影响。在两种滤纸接触测试中，温度升高加剧了CTD的急性毒性（48小时中位致死浓度（LC50）从20°C的0.077μg/cm2降低到30°C的0.009μg/cm2）和自然土壤测试（48小时LC50从20°C的0.774mg/kg降低到30°C的0.199mg/kg）。暴露于CTD或高温（30°C）会引发活性氧（ROS）过量产生，并增加蚯蚓的抗氧化酶活性；暴露于较高温度和CTD后，效果特别明显。在20和25°C时，暴露于CTD污染的土壤56天后，fetida的生长和繁殖没有显着变化。然而,CTD和高温（30°C）的联合作用显着降低了重量变化率，茧号,孵化率,以及第56天的青少年数量。这些结果表明，高温可加重CTD对蚯蚓的急性和慢性毒性。研究结果强调，评估全球变暖下农药毒性的变化值得进一步研究。
