Egg Diapause and Ambient Oxygen Tension in the False Melon Beetle, Atrachya menetriesi FALDERMANN(Coleoptera : Chrysomelidae)
1974 年 9 巻 4 号 p. 261-270
詳細
1974 年 9 巻 4 号 p. 261-270
The influence of ambient O2 on diapause was investigated in the egg of Atrachya menetriesi.When the diapausing eggs were chilled at 7.5°Cin N2 or CO2, they did not terminate diapause, even after 250 days of chilling, although they were almost completely free from diapause after an exposrue to the same temperature of 70 days in air. When the eggs were chilled in O2-deficient water, they required a much longer for the termination of diapause than in tap water. On the other hand, when the non-diapause eggs were transfferred to N2 from air, they ceased to developed regardless of the stage of embryonic development. If they were kept in a gaseous mixture of 5% O2 and 95% N2 from the 3rd day after oviposition, the embryo grew very slowly and ceased to develop at the appendage-formation stage, which was almost indistinguishable from the morphological stage of diapause. On the basis of these observations, it seems that O2 is indispensable for the termination of diapause and that the onset of diapause is in some way related to O2-deficiency in the egg.
