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重金属的污染及其治理是目前倍受关注的生态学问题之一.甜菜夜蛾是我国长江流域及以南地区蔬菜、棉花等作物上的主要害虫,近几年突发趋势明显.本文以甜菜夜蛾为靶标对象,设计5个浓度(0.3、1.2、4.8、19.2、76.8 mg·kg-1)重金属Pb2+处理,探讨处理后甜菜夜蛾各虫态体内Pb2+的积累和排泄,并根据甜菜夜蛾各虫态的生长与存活情况,构建了该虫连续3个世代的种群生命表.结果表明:取食含有不同浓度Pb2+的人工饲料后,各虫态甜菜夜蛾体内Pb2+的浓度在同一世代不同处理间存在显著差异,且呈显著的剂量-反应关系.各虫态体内Pb2+的浓度基本上随胁迫世代数的延长而增加.受Pb2+胁迫后,各虫态体内Pb2+的浓度顺序为5龄幼虫>成虫>蛹;该虫可通过粪便、预蛹蜕和蛹壳排泄体内部分重金属,且粪便和预蛹蜕中的Pb2+浓度远大于蛹蜕中的浓度;根据Pb2+不同浓度条件下甜菜夜蛾各虫态的存活率、雌性比和产卵量,构建的种群生命表表明,低浓度Pb2+胁迫可促进甜菜夜蛾的种群增长,而高浓度胁迫使种群增长衰退;且随着重金属的持续胁迫,其种群衰退更明显.研究结果为长期、客观评价重金属的危害性以及对重要农业害虫的种群影响提供了借鉴.
Heavy metal pollution and its control are one of the ecological problems that have drawn a lot of attention at present.The beet armyworm is a major pest on crops such as vegetables and cotton in the Yangtze River valley and the south of our country and has a clear trend in recent years.In this paper, Five concentrations (0.3, 1.2, 4.8, 19.2 and 76.8 mg · kg-1) of heavy metal Pb2 + were designed to investigate the accumulation and excretion of Pb2 + in the beet armyworm (Spodoptera exigua) The results showed that the concentration of Pb2 + in the beet armyworm (Spodoptera exigua) was the same in the same generation after feeding artificial diet containing different concentrations of Pb2 + There was significant difference between different treatments, and showed a significant dose-response relationship.Each Pbz + concentration in vivo increased with the increase of stress generation number.Under Pb2 + stress, the order of Pb2 + Larvae> adult> pupae. The insects excreted some heavy metals in the excrement, pre-pupae and pupa shell, and the concentration of Pb2 + in excrement and pre-pupae was much higher than that in the pupae. According to the results of different concentration of Pb2 + The worm state Survival rate, fecundity and fecundity. The constructed population life table showed that Pb2 + stress at low concentration promoted the population growth of Spodoptera exigua, while the population growth declined with high concentration of stress. With the continuous stress of heavy metals, the population decline More obvious.The results provide a reference for the long-term and objective evaluation of the harmfulness of heavy metals and the impact on the population of important agricultural pests.