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Pb2+在甜菜夜蛾体内的积累及对种群的影响

胡蒙蒙,蔡文宸,苏宏华,杨益众**   

  1. (扬州大学园艺与植物保护学院, 江苏扬州 225009)
  • 出版日期:2014-04-18 发布日期:2014-04-18

Accumulation of lead in Spodoptera exigua (Hübner) and its impact on the population.

HU Meng-meng, CAI Wen-chen, SU Hong-hua, YANG Yi-zhong   

  1. (School of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, Jiangsu, China)
  • Online:2014-04-18 Published:2014-04-18

摘要:

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.
 

Abstract: The heavy metals pollution is one of the ecological problems which have been paid close attention to Spodoptera exigua Hübner, one of the key pests on vegetables and cotton in the Yangtze River and its southern area in China, has broken out more frequently in recent years. In this study, accumulation of Pb2+ in S. exigua and its excretion were detected when fed with artificial diets with different Pb2+ concentrations (0.3, 1.2, 4.8, 19.2 and 76.8 mg·kg-1, respectively). Life table was constructed according to the survival and growth of different stages of S. exigua. The effect of lead on three successive generations of beet armyworm was studied using the life table in the laboratory. It was found that the Pb2+ contents were significantly different when S. exigua was reared at different Pb2+ concentrations in the same generation in a significant dosedependent manner. The concentration of Pb2+ increased with prolonging the stress time at the same time. The Pb2+ concentrations at the three developmental stages of beet armyworm followed the order of larvae > adult > pupa. The beet armyworm could excrete heavy metals by means of faeces, prepupa exuviate and puparium, and the concentrations of Pb2+ in faeces and prepupa exuviate were far higher than in puparium. According to the survival rates of different developmental stages, the female ratios and the egg numbers, the laboratory population life table was constructed. It showed that low doses of Pb2+ promoted the growth of the population, and high doses inhibited the growth, and the index of population trend (I) declined more rapidly with the increase of stress time. The study could provide references for longterm and objective assessment of heavy metal hazard and its effect on the populations of important agricultural pests.