Effects Of Wilforine And Wilforgine On The Muscular Structure In Mythimma Separata Walker (Lepidopyera:Noctuidae)

Wilforine and wilforgine are two main bases of the insecticidal activity of Tripterygium wilfordii alkaloids,which can cause pest and their muscle paralysis.Exploringtheir mechanisms for revealing the alkaloids of Tripterygium wilfordii are representative.In this study,westarts the research from the stomach toxicity test,symptomatic observation,histological study and optical microscopy,ultrastructural studies and electron microscopy and other aspects,and test results showed as followed: 1.Wilforine and wilforgine had oral toxicity against Mythimma separata larvae and adults.The LC50 values of the larvae were 63.22 and382.66(48 h)for the fifth instar larvae of Mythimna separata,respectively.The LC50 values of the adults were 35.75 and194.53(24 h),respectively.And the control agent chlorantraniliprolealsohad oral toxicity against M.separata larvae and adults.The LC50 values of the larvae andadultswere 0.16 ?g / mLand 0.12 ?g / mL,respectively.2.Wilforine caused that larvae and adults of Mythimna separata were gradually paralyzed,and then stopped feeding and finally died.The degrees of poisoning could be divided into three stages: mild anesthesia,moderate anesthesia and deep anesthesiaperiod.So the similar signs of poisoning caused by wilforgine,and the only difference was that wilforgine worked slow,and put off 0.5 to 1 hourmore than wilforine.Whilechlorantraniliprole caused the reverse signs of poisoning compared with wilforine.Test insects were gradually paralyzed,and bodyatrophic.Then were unable to feed,and finally dead.The length of death was about one-third of the control groups,but chlorantraniliproleworked faster than wilforine about 20 to 30 minutes.The degrees of poisoning could be divide into three stages: mild poisoning,moderate poisoning and deep poisoning period.3.The pathological changes occurred in the muscular tissue of the larvae and adults treated with wilforine.The results of optical micrography showed that there were disordered muscular tissue structure with increasing muscle fiber space,digested sarcolemma and disappeared band structure;Further,ultrastructural study and the results of electron microscopy showed shed myolemma,swollen mitochondria and dilated sarcoplasmic in the muscle cells;Moreover,the damage to the muscle cells increased with poisoning time.The effect of wilforgineon the muscular system of Mythimna separata was similar to that of wilforine.Chlorantraniliprole had a serious destructive effect on muscular structure and the membrane and endometrial system of muscle cells of Mythimna separata,which were roughly the same as that of wilforine.But there were also significant differences.The optical and electron microscopic results showed that the muscle fiber spacing of the poisoning insects shortenedlike squeezing,and sarcomere became shortened too.But some myofibrils also ruptured.So we can conclude from the above test results: wilforine,wilforgine and chlorantraniliprole had a strong oral activity on the armyworm.The orders of vitality from high to low were:chlorantraniliprole,wilforine,wilforgine.The tipical signs of poisoning treatment with the two alkaloids were paralysismuscle relaxation,and finally dead.chlorantraniliprole caused muscle shrinking and leading to deaths.The action sites of wilforine and wilforgine maybe locate in the muscular structures of insects.The molecular targets of two alkaloids may be consistent,but different from that of chlorantraniliprole.