Effect Of Diapause On Protein, Nucleic Acids And Flight Capacity Of The Beet Webworm, Loxostege Sticticalis (Lepidoptera:Pyralidae)

The beet webworm, Loxostege sticticalis L.(Lepidoptera:Pyralidae), which not only has long distance migration characteristic, also has the winter diapause characteristic. Because the characteristics of the diapasuse source and the regularity of diapause overwintering were not studied systematically, there is a hard road on forecasting and controlling this pest. In order to improve the forecasting and controlling technology of beet webworm based on the physiological and ecological factors of population dynamics, this thesis mainly focused on changes in protein and nucleic acid contents during diapasuse, alterations in the composition of proteins during diapasuse, the effects of diapause on the post-diapause adult ovarian development and flight potential, the major results were obtained as follows:Changes in proteins and nucleic acids contents between nondiapause and diapausing larvae. we analyzed the contents of proteins and nucleic acids in nondiapause larvae, diapausing larvae with diapause duration1,2,3, and4months, and postdiapause larvae of this species by using Trizol method, DNA and protein quantitative kit, SDS-PAGE technique. The results showed that the RNA content in the diapausing larvae with the diapause duration1to4months was significantly lower than that of the nondiapause larvae, although RNA content in the postdiapause larvae increased significantly as compared with that of diapausing larvae with the diapause duration2,3and4months, it was significantly lower than that of the nondiapause larvae. The DNA content among these treatments was not significantly different, but the RNA/DNA ratio in diapausing larvae with the diapause duration1to4months was lower than that in nondiapause and postdiapause larvae. The protein content in all the diapause larvae was significantly higher than that in the nondiapause larvae, but there were no significant difference between nondiapause and postdiapause. A protein band of24kDa was found in the diapausing larvae with the diapause duration1to4months but was not detected in the nondiapause and post diapause larvae by using the SDS-PAGE technique. All these results suggest that the lower RNA content, the lower RNA/DNA ratio, and higher protein content, as well as the presence of24kDa-protein are the major characteristics of diapause larvae distinguishing from the nondiapause and postdiapause larvae of L. sticticalis.Proteomic alteration of nondiapause and diapausing larvae. we analysis proteome between the nondiapause and diapausing larvae by using2D gel electrophoresis and peptide mass fingerprint (PMF), we identified14proteins in the beet webworm with diverse functional characteristics, including cytoskeleton, ATPases, proteins regulating signal pathway and enzymes involved in metabolism. A proteomic comparison between nondiapause and diapausing larvae revealed six proteins that were present only in nondiapause larvae, which are ATP synthase beta subunit, Myosin heavy chain, Tubulin beta-1chain,14-3-3zeta,14-3-3zeta and14-3-3epsilon protein. But Myosin heavy chain (muscle) that was present only in diapausing larvae. Understanding protein expression differences of diapause and non-diapause larvae will enable us to further characterize the regulated functions of diapause. It is very useful to explores the diapause related genes and proteins of L sticticalis. It is also very useful to reveals proteomics and molecular regulation mechanism of L. sticticalis.Effects of diapause on ovarian development and flight capacity. In order to elucidate the effects of diapause treatment and diapause duration to the beet webworm on the reproduction system and flight system, the ovarian development grade, preoviposition period, Oviposition period, thoracic dorsal-longitudinal muscle weight, triglyceride content and flight potential of the treatment moths (diapause durations2.5months and5months) and the control moths(nondiapause) of the beet webworm were studied systematically. The results showed that the ovary of postdiapause females developed more slowly than that of the nondiapause females. The pre-oviposition period and Oviposition period of postdiapause females was significantly longer than that of nondiapause females. The pre-oviposition period and Oviposition period between diapause durations2.5months and5months were similar. Total egg production among these treatments were not significantly different. There is a positive phenotypic correlation between diapause and flight potential, flight capacity of postdiapause moths were significantly greater than that of nondiapause moths. Dry weight of the thoracic dorsal-longitudinal muscle and the triglyceride content of postdiapause moths was significantly higher than that of nondiapause moths. However, flight capacity of diapause duration2.5months moths were greater than that of diapause duration5months moths. Dry weight of the thoracic dorsal-longitudinal muscle and the triglyceride content of duration2.5months was higher than that of duration5months moths. The results showed that diapause can inhibit reproduction of L. sticticalis significantly, but diapause can promote flight of L. sticticalis significantly. The beet webworm after diapausing can still find perfect habitat by migrating.