Some Inhibitory Actions of Corpora Allata in Diapausing Larvae of the Rice Stem Borer, Chilo suppressalis WALKER : (Lepidoptera : Pyralidae)

抄録

Implantation of a diapause brain into a diapusing Chilo larva did not cause the immediate termination of the larval diapause. But the same treatment terminated the diapause of decapitated larva. On the other hand, a diapause brain connected with the corpora cardiaca and corpora allata which was implanted into the decapitated diapausing larva produced little effect on the maintenance of diapause. These were quite different from the results shown in Ostrinia larva by CLOUTIER et. al. (1962). As a trial to approach the solution of the substantial relationship between the corpus allatum and the brain, some model experiments were conducted using physiologically active substances known to act like brain hormones in silkworms. Among the substances tested, cholesterol, diethylstilbestrol and noradrenaline induced the moulting of the headless, diapausing larva, though its percentage was low, wheras enone of them produced any physiological change in the intact diapausing one. Namely the activity of the chemicals was apparently inhibited in the intact diapausing larva. These results and others hitherto obtained seemed to give the evidence that the corpus allatum was responsible for maintenance of rice etsm borer larva in diapause.