Effects of insecticide exposure on feeding inhibition in mayflies and oligochaetes
Effects of insecticide exposure on feeding inhibition in mayflies and oligochaetes
复制标题
DOI：
10.1897/07-015r.1
复制
发表时间：
2007-08-01
影响因子：
4.1
通讯作者：
Cessna, Allan J.
中科院分区：
文献类型：
--
作者：
Alexander, Alexa C.;Culp, Joseph M.;Cessna, Allan J.
本研究探讨了脉冲暴露的杀虫剂吡虫啉对蜉蝣，Epeorus longimanus伊顿（家庭Heptageniidae），和水生寡毛类，Lu rbriculus variegatus梅勒（家庭Lumbriculidae）的影响。脉冲暴露的吡虫啉是特别相关的检查，因为这种杀虫剂是相对可溶的（510毫克/升），最有可能在径流事件的影响浓度。实验研究了24小时脉冲暴露于吡虫啉超过环境现实的浓度范围（0，0.1，0.5，1，5，和10微克/升）的生物体的恢复。通过定量蜉蝣消耗的藻类生物量或寡毛纲动物排泄的食物来测量对摄食的影响。吡虫啉具有高度毒性，在早期蜉蝣龄期和较大的晚期蜉蝣龄期中，24小时半数致死浓度较低（24小时半数致死浓度，2.1 +/- 0.8微克/升; 96小时半数致死浓度，0.65 - 0.15微克/升）。短（24小时）脉冲超过1微克/升的吡虫啉引起摄食抑制，而恢复（4天）变化，这取决于污染物暴露后的天数。与蜉蝣相反，寡毛螨在短（24小时）脉冲期间对吡虫啉相对不敏感;然而，在4天连续暴露实验期间观察到寡毛螨不动，96小时有效浓度中位数为6.2 +/- 1.4 μ g/L。总体而言，浓度大于0.5但小于10 μ g/L的吡虫啉降低了蜉蝣和寡毛类的存活率、摄食和排泄。摄食和排泄抑制表明对该杀虫剂的生理和行为反应。
The present study examined the effects of pulse exposures of the insecticide imidacloprid on the mayfly, Epeorus longimanus Eaton (Family Heptageniidae), and on an aquatic oligochaete, Lu rbriculus variegatus Mailer (Family Lumbriculidae). Pulse exposures of imidacloprid are particularly relevant for examination, because this insecticide is relatively soluble (510 mg/L) and is most likely to be at effect concentrations during runoff events. Experiments examined the recovery of organisms after a 24-h pulse exposure to imidacloprid over an environmentally realistic range of concentrations (0, 0.1, 0.5, 1, 5, and 10 mu g/L). Effects on feeding were measured by quantifying the algal biomass consumed by mayflies or foodstuffs egested by oligochaetes. Imidacloprid was highly toxic, with low 24-h median lethal concentrations (LC50s) in early mayfly instars (24-h LC50, 2.1 +/- 0.8 mu g/L) and larger, later mayfly instars (24-h LC50, 2.1 +/- 0.5 mu g/L; 96-h LC50, 0.65 0.15 mu g/L). Short (24-h) pulses of imidacloprid in excess of 1 mu g/L caused feeding inhibition, whereas recovery (4 d) varied, depending on the number of days after contaminant exposure. In contrast to mayflies, oligochaetes were relatively insensitive to imidacloprid during the short (24-h) pulse; however, immobility of oligochaetes was observed during a 4-d, continuous-exposure experiment, with 96-h median effective concentrations of 6.2 +/- 1.4 p.g/L. Overall, imidacloprid reduced the survivorship, feeding, and egestion of mayflies and oligochaetes at concentrations greater than 0.5 but less than 10 mu g/L. Inhibited feeding and egestion indicate physiological and behavioral responses to this insecticide.