Brain-suboesophageal Ganglion Research Articles

Hormonal studies on the diapause and non-diapause eggs of the silkworm, Bombyx mori L.

It is known that the brain-suboesophageal ganglion complex in the silkworm converts the non-diapause egg into the diapause egg. It has been found that the corpus allatum is concerned not only with the number of moults but also with the production of non-diapause eggs. The influence of the suboesophageal ganglion differs with each voltine race, and it gradually becomes stronger with age, whereas the influence of the corpus allatum differs with each moulting race and becomes weaker with age. The brain does not perfectly control the secretion of both the suboesophageal ganglion and the corpora allata, but weakly inhibits and also weakly promotes their secretory activity. The corpus allatum and suboesophageal ganglion hormones consist not only of non-diapause and diapause hormones, but also of growth-promoting and inhibitory hormones.

Functions of the Central Nervous System in Relation to Quantitative Characters in a W-Translocated strain of Silkworm, <i>Bombyx mori</i> L.

(1) Although the silk-layer weight of females is usually heavier than that of males in the common silkworm strain, this relation is reversed in the W-translocated strain.(2) The functional relationships among the three organs, brain, suboesophageal ganglion and corpora allata which are related to quantitative characters such as the weight of the silk-layer and voltinism were examined in a series of experiments in organ transplantation.(3) By transplantation of the brain-suboesophageal ganglion complex of females of the W-translocated silkworm strain to “non-diapause larvae” the silk-layer weight of the recipient is more decreased and voltinism is more strongly changed in non- diapause direction than in the case of transplantation of suboesophageal ganglion alone.(4) By transplantation of the brain-suboespohageal ganglion complex of males of the W-translocated silkworm strain to “non-diapause larvae” the silk-layer weight of the recipients is more increased and the voltinism is more strongly changed in diapause direction than in the case of transplantation of the suboesophageal ganglion alone.(5) By transplantation of the brain-corpora allata complex of females of the W-translocated silkwrom strain to “diapause larvae” the silk-layer weight of the recipients is more decreased and the frequency of non-diapause eggs within one batch becomes higher than by transplantation of corpora allata alone.(6) By transplantation of the brain-corpora allata complex of males of the W- translocated silkworm strain to “diapause larvae” the silk-layer weight of the recipient is more increased and the percentage of non-diapause eggs in one batch (laid by one moth) is more decreased than in the case of transplantation of corpora allata alone.(7) It is assumed from the above-mentioned findings that the brain of females of the W-translocated strains weakly inhibits the functional activity of suboesophageal ganglion and weakly acclerates that of corpora allata through nerve commissures. It seems, on the contrary, that the brain of males of the same strain weakly accelerates the functional activity of suboesophageal ganglion and weakly inhibits that of corpora allata through the nerve commissures.

Function of the Brain-Suboesophageal Ganglion Complex in the Silkworm, Bombyx mori

Function of the Brain-Suboesophageal Ganglion Complex in the Silkworm, Bombyx mori