Studies On The Physiological And Biochemical Mechanism Of Diapause Pupae Of Oriental Tobacco Budworm, Helicoverpa Assulta

Diapause is one strategy by which insects adapt to the seansonal environmental changes during the long period evoluation. But the physiological mechanism about insects diapause is still controversial.In the artificial condition, the tobacco budworm, Helicoverpa assulta were induced diapausing from the third instar larvae. Overwintering survival rate of diapause and non-diapause pupae was determined in the natural condition at December, 2003; At one time cold hardiness of diapause and non-diapause pupae was determined in the door.The changes of main biochemical and physiological composition of diapause and non-diapause pupae were studied, such as fresh weight, dry weight, weight loss, water content, supercooling point, freezing point, respiratory intension (CO2 release), fat, glucogen, haemolymph proteins, glycerol and so on. The main results are as follows: 1, Overwintering survival rate of diapause pupae was higher than non-diapausepupae. the result indicated that the cold hardiness of diapause pupae was tallerthan non-diapause pupae.2, Supercooling point of diapause pupae was lower than non-diapause pupae.According to the relationship between cold hardiness and supercooling point, diapause pupae has greater potential in anti-cold hardness than non-diapause pupae.3 , Fresh weight and water content of diapause pupae decreased, but the dry weightincreased. It is the strategy that the tobacco budworm get throuth winter. 4, Fat content of diapause pupae is higher than non-diapause pupae, fat is primaryenergy source during diapause. 5, Glucogen content of diapause pre-pupae is higher than non-diapause pupae; Andthe content was reduced along with pupae stage increasing. At stage of the third...