Department of System Ecotoxicology, Helmholtz Centre for Environmental Research (UFZ), Permoserstrasse 15, 04318 Leipzig, Germany.
Department of System Ecotoxicology, Helmholtz Centre for Environmental Research (UFZ), Permoserstrasse 15, 04318 Leipzig, Germany.
Aquat Toxicol. 2014 Feb;147:26-31. doi: 10.1016/j.aquatox.2013.12.002. Epub 2013 Dec 11.
The effects of multiple insecticide pulses on non-target organisms have rarely been investigated in combination with relevant biotic interactions, such as competition. In this study, we examined the effects of two repeated pulses of the insecticide pirimicarb (3, 10, 24 μg/L) on populations of Daphnia magna with or without competition. To investigate the influence of competition, half of the test systems were supplemented with the pirimicarb-insensitive species Culex pipiens. The pesticide pulses were followed by a recovery period of 28 days, which corresponded to approximately three generation times for D. magna. The one-species setup with the Daphnia populations and the two-species setup with both the Daphnia and Culex populations had a precontamination period of 30 days so that intra- and interspecific competitions were present prior to the insecticide pulse. Short-term effects on the survival of the Daphnia population were observed in both setups immediately after each insecticide pulse at the highest concentration level. In the one-species setup, the short-term effects on population survival were increased by intraspecific competition. However, the Daphnia populations in the one-species setup recovered and reached the control level within approximately two weeks after each insecticide pulse. In contrast, in the two-species setup at the highest concentration, we observed culmination of insecticide effects: the Daphnia populations did not recover and their abundance was below the control level until the end of the observation time. Their recovery was impeded by the presence of the competing species C. pipiens for at least four weeks. At low concentrations, no culmination of effects was observed. We conclude that repeated toxicant pulses on populations that are challenged with interspecific competition may result in a multigenerational culmination of toxicant effects.
多次杀虫剂脉冲对非靶标生物的影响与相关生物相互作用（如竞争）结合起来很少被研究过。在这项研究中，我们研究了两次重复施用杀虫剂啶虫脒（3、10、24μg/L）对有或没有竞争的大型溞种群的影响。为了研究竞争的影响，一半的测试系统补充了对啶虫脒不敏感的物种库蚊。杀虫剂脉冲后，经过 28 天的恢复期，这相当于大型溞的大约三个世代时间。有大型溞种群的单物种设置和有大型溞和库蚊种群的双物种设置都有 30 天的预污染期，以便在杀虫剂脉冲之前存在种内和种间竞争。在两个设置中，即在最高浓度水平下，在每次杀虫剂脉冲后立即观察到对大型溞种群存活的短期影响。在单物种设置中，种内竞争增加了对种群存活的短期影响。然而，在一次杀虫剂脉冲后，单物种设置中的大型溞种群在大约两周内恢复并达到对照水平。相比之下，在最高浓度的双物种设置中，我们观察到杀虫剂效应的累积：大型溞种群没有恢复，其丰度低于对照水平，直到观察时间结束。至少在四周内，竞争物种库蚊的存在阻碍了它们的恢复。在低浓度下，没有观察到效应的累积。我们得出结论，受到种间竞争挑战的种群受到多次有毒剂脉冲的影响，可能会导致有毒剂效应的多代累积。
