溴氰菊酯对萼花臂尾轮虫实验种群动态的影响

Effect of deltamethrin on experimental population dynamics of freshwater rotifers Brachionus calyciflorus

采用生命表技术对暴露于不同浓度溴氰菊酯溶液中的萼花臂尾轮虫的存活和繁殖进行了研究。结果显示, 溴氰菊酯使轮虫的存活时间显著缩短, 繁殖率降低; 当溴氰菊酯浓度高达3 6 mg/L时, 轮虫的存活时间最短、繁殖率最低。与对照组相比, 除1 2 mg/L外, 其它各浓度的溴氰菊酯均使轮虫的生殖前期显著延长; 浓度为0 6和1 2 mg/L的溴氰菊酯使轮虫的生殖期显著延长, 而浓度为2 4和3 0 mg/L的溴氰菊酯却使轮虫的生殖期显著缩短; 1 2 mg/L的溴氰菊酯使轮虫的平均寿命显著延长。轮虫的生命期望、世代时间、净生殖率和种群内禀增长率均随溴氰菊酯浓度的升高而下降。当溴氰菊酯浓度升高达1 2 mg/L时, 轮虫的净生殖率开始与对照组有显著差异; 而轮虫的种群内禀增长率从溴氰菊酯浓度升高达2 4 mg/L时才开始与对照组有显著差异。在溴氰菊酯的毒性监测中, 净生殖率是比种群内禀增长率更敏感的指标。

Using life-table techniques, we studied the effect of deltamethrin whose experimental concentrations were 0.6, 1.2, 1.8, 2.4, 3.0 and 3.6 mg/L on experimental population dynamics of freshwater rotifer Brachionus calyciflorus at 25 °Effect of deltamethrin on experimental population dynamics of freshwater rotifers Brachionus calyciflorus*$$$$ XU Xiao-Ping, XI Yi-Long **, CHU Zhao-Xia, CHEN FangCollege of Life Science,Anhui Normal University,Provincial Laboratory of Conservation and Utilization for Important Biological Resource in Anhui, Wuhu 214000, China Abstract Using life-table techniques, we studied the effect of deltamethrin whose experimental concentrations were 0.6, 1.2, 1.8, 2.4, 3.0 and 3.6 mg/L on experimental population dynamics of freshwater rotifer Brachionus calyciflorus at 25 °[KG-*9C and with 3.0×106 cells/ml of alga Scenedesmus obliquus as the rotifer’s food. The results showed that deltamethrin shortened the survival time, and lowered the fecundity of the rotifer. When the concentration of deltamethrin was 3.6 mg/L, the survival time and fecundity of the rotifer was the shortest and lowest, and was 72 h and less than 1 offspring/female/8 h, respectively. Compared to the control, deltamethrin ranged from 0.6 to 3.0 mg/L prolonged the pre-reproductive period significantly from (16.48±0.30)h to (20.95±0.97)h, except 1.2 mg/L of deltamethrin at which the pre-reproductive period was (15.83±0.29)h. The reproductive periods of the rotifer treated with 0.6 and 1.2 mg/L of deltamethrin were respectively (89.83±2.30)h and (106.58±4.88)h, and were significantly longer than that of the control which was (78.29±2.89)h; while those treated with 2.4 and 3.0 mg/L of deltamethrin were respectively (70.13±2.61)h and (48.14±2.52)h, and were significantly shorter than that of the control. 1.2 mg/L of deltamethrin lengthened the mean life span significantly. The life expectancy, generation time, net reproductive rate and intrinsic rate of population increase of the rotifers decreased respectively from (135.62±6.37)h, (58.81±1.62)h, (28.47±0.59)ind. and (0.0802±0.0026)/h to (81.39±5.04)h, (46.31±2.12)h, (6.32±2.11)ind. and (0.0431±0.0126)/h with the rise of deltamethrin concentration from zero to 3.0 mg/L. The net reproductive rate was more sensitive than the intrinsic rate of population increase, because the lowest concentration that the net reproductive rate began to differ significantly from the control was 1.2 mg/L, but for the intrinsic rate of population increase it was 2.4 mg/L.