著者

日高 敏隆 米川 誠

出版者

日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.68, no.1, pp.27-31, 1959-01

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In full-grown larvae (50mm or a little more in body length) of Malacosoma neustria testacea Motschulsky, extirpation of either the prothoracic or the mesothoracic ganglion results in a marked distension of the body within about 24 hours. The body becomes fully stretched, attaining about 70mm in length. The larvae become almost unable to move, except that they show a continuous biting and swallowing movement of mouth-parts. The alimentary canal is filled with air thus swallowed. When punctured by needle, the air escapes from the alimentary canal and the body immediately becomes reduced in size (see Figs. 1 and 2). After removal of the subesophageal ganglion or of the brain, the mouth-parts become immobile. In these larvae, extirpation of the prothoracic ganglion no longer causes the distension of the body. If the mouth and anus are closed with paraffin immediately after removal of the prothoracic ganglion, no distension of body can be observed. It is obvious, therefore, that the body distension following removal of the prothoracic ganglion is largely attributable to an abnormal intake of excess amount of air into the alimentary canal. Extirpation of the prothoracic ganglion appears to bring about a failure of a proprioceptic inhibitory mechanism. In younger larvae, mature larvae or prepupae no distension of body takes place after removal of the prothoracic ganglion. In the silkworm (Bombyx mori, L., J-122×C-115) deprived of the prothoracic ganglion, the distension is very slight.