三唑磷和毒死蜱亚致死剂量对大螟种群增长和卵黄蛋白含量的影响

Effects of sublethal doses of triazophos and chlorpyrifos on the population growth and yolk protein content of Sesamia inferens(Walker)

【目的】本文研究了三唑磷和毒死蜱LC20/LD20浓度对大螟Sesamia inferens(Walker)种群增长和卵黄蛋白含量的影响,为揭示大螟田间种群猖獗的生态机制提供科学依据。【方法】分别采用浸渍和点滴法测定了三唑磷和毒死蜱对大螟1龄和3龄幼虫的毒力,并测定了LC20/LD20的两种药剂处理后大螟种群增长参数和卵黄蛋白含量的变化。【结果】大螟幼虫对三唑磷的敏感性显著高于毒死蜱。三唑磷LC20处理大螟幼虫1龄期显著增加了蛹重和产卵量,且1龄、3龄期的两次处理除了明显增加蛹重和产卵量外,还显著增加了卵黄蛋白含量。毒死蜱LC20/LD20浓度对大螟种群增长影响不明显。【结论】三唑磷亚致死剂量刺激大螟生殖,有利其种群的增长。

[Objectives] To understand the ecological mechanisms of natural population growth of the pink stem borer （PSB） Sesamia inferens （Walker）, and the effects of sublethal doses of striazophos and chlorpyrifos on its population growth and yolk protein content. [Methods] The toxicity of triazophos and chlorpyrifos, and their effect on population growth parameters and yolk protein content, were assessed using the dipping and topical application methods for 1st and 3rd instar larvae respectively. [Results] Our results indicate that larvae were more sensitive to triazophos than chlorpyrifos. The weight of pupae developed from 1st and 3rd instar larvae treated with LC20 or LD20 of triazophos, the number of eggs laid by emergent adult females, and the yolk protein content of females all increased significantly. In contrast, chlorpyrifos had no obvious effect on population growth. [Conclusion] Our findings indicate that sublethal doses of triazophos stimulate the reproduction of PSB and may thereby promote outbreaks of this pest.