Investigation Of Biological Activity And Mechanism On IGRs Against Tribolium Castaneum

This paper mainly studied: (1)The lethal effects of Diflubenzuron,Chlorfluazuron,Hexaflumuron,Flufenoxuron,Flucycloxuron,Chlorbenzuron,Buprofezin,Osthole,Pyriproxyfen,Methoprene on Tribolium castaneum; (2)the impact of Pyriproxyfen and Osthole on the growth and development of the larva of Tribolium castaneum; (3) the impact of Chlorfluazuron on the chitin synthesis process of the larva of Tribolium castaneum at molecular level.Mixed with food was adopted to sift growth regulator for ten kinds of insects. According to the results, under the concentration of 40 mg/kg,20 mg/kg and10 mg/kg the corrected morality rates of Chlorfluazuron on the larva of Tribolium castaneum are 94.11%,88.23% and 82.35% respectively, which is obviously higher than that of other regulator and have significant lethal effects on the larva of Tribolium castaneu -m. Chlorfluazuron can hinder the form of new epidermis of larvae,suspend its development, make it not hard enough to exuviate, lead to death or abnormal pupa. Pyriproxyfen has no apparent lethal effects on the larva of Tribolium castaneum,but it can expand its time of growth and make it stay as the last-instar larva and cannot become a pupa, which leads to abnormality and death. Osthole does not have a higher morality death rate on Tribolium castaneum, but it can restrain the pupa from becoming larva and lead to its abnormality and death.Given the fact that Chlorfluazuron has a higher fatality rate on Tribolium castaneum, this paper adopts RT-PCR and Real-time PCR to study the impact of Chlorfluazuron on the chitin synthesis process of the larva of Tribolium castaneum at molecular level,and makes a preliminary study about its impact and mechanism on genes TcCHS1, TcCHT5 and TcCHT10.As shown by the results,the expression value of gene TcCHS1 of treatment group is 2.35 times that of the control group, while the expression value of genes TcCHT5 and TcCHT10 of treatment group shows no obvious change before and after drug delivery. Thus the paper infers that after the expression of Chitin synthase compensatory caused by Chlorfluazuron , it may lead to the redundancy of chitin synthase.Excessive chitin synthase will gather around the membrane and affect the dimensional structure of this large Oligodendrocyte transmembrane protein and intervene the normal form of chitin and the exuviation and development of Tribolium castaneum, which may die from unsuccessful exuviation.