雷公藤吉碱对粘虫成虫飞行肌结构的影响

Effects of wilforgine on flight muscular structure in adult Mythimna separata(Lepidoptera:Noctuidae)

【目的】明确雷公藤吉碱对粘虫Mythimna separata成虫飞行肌结构的影响,为进一步探讨其杀虫机理奠定基础。【方法】采用饲喂法测定了雷公藤吉碱对粘虫成虫的胃毒活性及致毒症状。采用光镜和透射电镜技术,从显微和超微水平观察雷公藤吉碱(300μg/mL)对粘虫成虫飞行肌结构的影响。【结果】雷公藤吉碱对粘虫成虫具有较强的胃毒作用,其24 h致死中浓(LC_(50))值为194.53μg/mL;试虫中毒的典型特征为麻痹致死;显微观察显示处理组试虫肌肉组织结构紊乱,肌纤维间距增大,肌膜消解,横纹结构消失,且随中毒程度的加深,病变程度加剧;超微观察显示处理试虫肌细胞结构破坏,肌膜脱落,线粒体肿胀,肌质网扩张,肌原纤维断裂,且随中毒程度的加深,病变呈渐进性加剧。【结论】雷公藤吉碱可致粘虫成虫飞行肌病变,影响肌肉正常收缩,从而引起试虫麻痹致死,其作用靶标可能位于肌肉系统。

【Aim】This study aims to investigate the effect of wilforgine on muscular structure against adults of the oriental armyworm,Mythimna separata,so as to provide basis for further studying its insecticidal mechanisms.【Methods】 M.separata adults were fed on acetone-sugar water solution of wilforgine to assay the toxicity and poisoning symptoms.The pathological changes in their muscular structure induced by wilforgine（300 μg/mL） were observed by light and electron microscope.【Results】Wilforgine had strong oral toxicity against M.separata adults with the LC50 value of 194.53 μg/mL.The typical toxicity sign was paralysis leading to death.Microstructural examinations demonstrated that the muscular structure was damaged with increasing spaces between muscular fibers.The sarcolemma was digested and band structures disappeared.The ultrastructural examinations showed shed myolemma,swollen mitochondria and dilated sarcoplasmic in the muscle cells.Moreover,the damage to muscle cells increased with poisoning time.【Conclusion】Wilforgine could induce pathological changes in the flight muscle of M.separata adults,leading to death.Thus,the action site of wilforgine may be located in the muscle tissues of this insect.