The Function And Regulation Mechanisms Of Juvenile Hormone During Flight Optimizing Reproduction Of Mythimna Separata (Walker)

Migration is an important factor influencing insect reproduction.Regulation mechanism at home and abroad for these phenomena is not clear.In the previous studies,we found the flight in the appropriate mode of Walkers will significantly promote reproduction,resulting in the disaster.In the results we know that flight 2 nights can promote the reproduction,while as flight more than 4 nights can significantly inhibit reproduction.The study based on Mythimna separate(Walker),a typical long distance migratory insects.We have been informed of the juvenile hormone(Juvenile hormone,JH)involved in the regulation between Walkers flight and reproduction,treatment with juvenile hormone analogues(Juvenile hormone analogue,JHA)to detect the effects of JH on spawning,ovarian and flight muscle development,to verify the function of JH in the flight promotion reproduction.The research about the JH synthesis and metabolism related allatotropin(AT),allatostatins(AST)and juvenile hormone esterase(JHE)gene,and the methoprene-tolerance(Met),we clone and characterize the Met gene,and the encoding regions full-length sequence;dected the changes of AT,AST,JHE and Met gene expression were detected by q-RT PCR.The main results are as follows:1,research makes clear the effects of JHA on the reproduction andlight system development.At 1day after emergence treatment with JHA the oviposition period significantly shortened,and the ovarian development was accelerated;the flight muscles showed significantly accelerated degradation,the shorter length and width of the flight muscle compared to the control,while treatment at the other day had no significant effect.After three days treatment with JHA at 1day,the flight muscles were degraded in advance,the color changed from fresh red to yellow,and the muscle fibers became loose and short.Therefore,JH is the key endocrine factors to inhibit the armyworm reproductive in flight systems.And the 1 day after the emergence is the critical period of armyworm.2,Cloning and identification of Met gene encoding region full-length of armyworm.The open reading length of the gene is 1575 bp,and encode 524 amino acids.The predicted protein molecular weight is 59.76 kDa,and the isoelectric point is 8.The Met gene nucleotide sequences is up to 70% with Helicoverpa armigera? Pectinophora gossypiella?Bombyx mori?Plodia interpunctella?Plutella xylostella.The gene has a typical HLH domain and PAS functional domain of Met gene family.3,The research clarified the JH related gene expression patterns.The expression of AT,AST and JHE has tissue and time specific expression significantly,and has obvious relevance with the oviposition.Before spawning the expression of AT gene is high,and AST and JHE is low.After oviposition,the expression of AT is significantly lower than before,and AST and JHE were significantly increased.In addition,the expression of AT gene in the head of the expression was significantly higher than that of flight muscle and ovary;expression of AST gene in the flight muscle were significantly higher than the head and ovary and JHE gene expression in fat body was significantly higher than that in flight muscle and ovary.4.The study identified the changes of the genes expression that regulate the synthesis andmetabolism of JH,as well as receptor gene expression under the stimulation of the two flight modes,which have the opposite effect on reproduction.In the promotion of flight(flight 2 nights),it promotes AT gene synthesizing JH expression significantly compared with the control and increase the expression of JHE gene degradating of JH,AST gene inhibiting of JH synthesis were significantly decreased;Met r gene expression in the ovary was significantly increased in advance;after flight 3 nights or more,with the increase of the number of flight nights,the expression of AT gene significantly decreased with the increased number of nights.The expression of AST and JHE gene increased significantly with the increase of the number of flight nights.The expression of Met gene in flight muscle was significantly increased with the number flight nights.These results suggest that the differences of JH synthesis and metabolism,and receptor gene expression is the key molecular regulation mechanisms of Mythimna separate during flight effecting reproduction.