Effect of Temperature of Incubation on Activation of Brain-Pro thoracic Gland System of Diapausing Pupae in Samia cynthia pryeri

Termination of diapause occurs with activation of brain-prothoracic gland system in diapausing pupae of Samia cynthia pryeri. It does not occur with 20℃ incubation, but it occurs with 26℃ incubation. To investigate the cause of this fact histological change of neurosecretory cells of pupal brain during incubation and effect of β-ecdysone injection were observed. In histological observation, phloxinophilic granules of lateral B type cells in pars intercerebralis decreased on and after the 5-th day of 20℃ incubation. Diapausing pupae developed into imagines with β-ecdysone injection during 20℃ incubation. From these results, it is concluded that fail of termination of diapause with 20℃ incubation is not resulted from the inactive state of neurosecretory cells in brain but it is resulted from the inactive state of ecdysone secretory system in this temperature.Article信州大学理学部紀要 21(2): 105-114(1987)departmental bulletin pape