【摘要】 <正> 蓖麻蚕(Philosamia cynthia,ricini)原产印度,是多化性的昆虫,在一生任何阶段中都不滞育,因此在生产实践上,解决蓖麻蚕越冬是一个重要的问题。一种野生的樗蚕(Philo-samia cynthia walkeri)和蓖麻蚕的血缘很近,是同一种中的不同亚种,但以蛹越冬。在阐明昆虫以蛹态滞育的生理机制上,有Williams(1946,1947,1952)在一种大型的天蚕蛾(Platysamia cecropia)的试验。他发现 P cccropia的蛹态滞育是由脑激素停止分泌所引起的。福田(1958)在蓖麻蚕和樗蚕的蛹脑移植试验上,证实了蓖麻蚕的多化性和樗蚕的更多还原

【Abstract】 Brains of Philosamia cynthia ricini were removed at die various periods after mounting in order to study the influence of the brain hormone upon pupation. Temperature was kept at 25℃throughout the experiments. Not a single larva operated within 4 hours after’ mounting pupated Among those larvae which were operated during 8 to 20 hours after mounting, only some of them pupated. Although all the larvae operated at 24 to 52 hours after mounting pupated, they obviously required much longer periods for pupation. Larvae operated 56 hours after mounting did not show any signs of delay for pupation. It appears likely that there is a critical period of the brain-hormone secretion for normal pupation in Philosamia cynthia ricini at 52-56 hours after mounting.Transplantion of the pupal brains of Philosamia cynthia ricini was also carried out at various periods to the diapausing pupae of Philosamia cynthia walkeri for the purpose of testing the influence of the brain hormone on imaginal differentiation. The results of the experiment indicate that the pupal brains of Philosamia cynthia ricini are able to terminate the diapause of the pupae of Philosamia cynthia wd^en and that within the 3rd day after pupation the brains of Philosamia cynthia ricini attain their peak in hormone secretion.The author also removed the brains of Philosamia cynthia ricini at various periods after pupation to test the influence of the brain hormone on imaginal differentiation. It seems that a critical period of the brain hormone for imaginal differentiation exists within 72 hours after pupation.By transplanting the brains of Philosamia cynthia ricini to the brainless, diapausing pupae of Actias science, it was observed that the brains of the former were able to terminate the diapause of the latter. It appears that the brain hormone of Philosamia cynthia ricini is not species-specific.更多还原