Concentration of Bifenthrin in Adult Insects That Emerged from Mesocosms

Direct and indirect ecological effects of the widely used insecticide bifenthrin on stream ecosystems are largely unknown. To investigate such effects, a manipulative experiment was conducted in stream mesocosms that were colonized by aquatic insect communities and exposed to bifenthrin-contaminated sediment; implications for natural streams were interpreted through comparison of mesocosm results to a survey of 100 Midwestern streams, USA. In the mesocosm experiment, direct effects of bifenthrin exposure included reduced larval macroinvertebrate abundance, richness, and biomass at concentrations (EC50s ranged 197.6 – 233.5 ng bifenthrin/ g organic carbon) previously thought safe for aquatic life. Indirect effects included a trophic cascade in which periphyton abundance increased after macroinvertebrate scrapers decreased. Adult emergence dynamics and corresponding terrestrial subsidies were altered at all bifenthrin concentrations tested. Extrapolating these results to the Midwestern stream assessment suggests pervasive ecological effects, with altered emergence dynamics likely in 40% of streams and a trophic cascade in 7% of streams. This study provides new evidence that a common pyrethroid might alter aquatic and terrestrial ecosystem function at the regional scale. This data included information about the adult aquatic insects that were analyzed for bifenthrin in their bodies.

当前学界对广泛使用的拟除虫菊酯类杀虫剂联苯菊酯（bifenthrin）对溪流生态系统造成的直接与间接生态效应仍知之甚少。为探究此类效应，研究人员在已定殖水生昆虫群落且暴露于联苯菊酯污染沉积物的溪流中宇宙（stream mesocosm）中开展了控制性实验。通过将中宇宙实验结果与美国中西部100条溪流的调查数据进行对比，本研究阐释了其对自然溪流的生态影响。在中宇宙实验中，联苯菊酯暴露的直接效应表现为：在以往被认为对水生生物安全的浓度（半效应浓度EC50范围为197.6~233.5 ng 联苯菊酯/克有机碳）下，大型底栖无脊椎动物幼虫的丰度、物种丰富度及生物量均显著降低。间接效应则表现为营养级联反应：大型底栖无脊椎动物刮食者种群减少后，周丛生物（periphyton）丰度显著上升。所有受试联苯菊酯浓度下，成虫羽化动态及对应的陆地生态补贴（terrestrial subsidies）均发生改变。将上述实验结果外推至美国中西部溪流调查数据，可发现联苯菊酯造成的生态效应具有普遍性：约40%的溪流可能出现成虫羽化动态改变，7%的溪流则可能发生营养级联反应。本研究为这类常见拟除虫菊酯类杀虫剂可能在区域尺度上改变水生与陆地生态系统功能提供了新的实证依据。
本数据集包含了体内联苯菊酯含量分析所用的成虫水生昆虫相关信息。