ウスタビガRhodinia fugaxの越年卵の発育零点について
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概要
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The embryos of Rhodinia fugax usually enter wintering at near the stage of appendage formation. With the rise of temperature toward March, their development is initiated again through the blastokinesis and hatching occurs early in April. The larvae which are fed on the cherry leaves become to pupate after attaining maximum growth early in July, and the pupae enter estivation for approximately 4 months, at the end of which the adults emerge early in November to copulate and make oviposition. In the present experiment, the wintering eggs laid early in November were kept at constant temperatures of 5°, 10°, 15°, 20° and 25℃ in order to observe the temperature effect upon the embryonic development. As the results following were observed: At 25℃ death occurred in all the specimens toward 72 days of incubation, when the stage of larval formation was attained. Hatching occurred in approximately 87 days at 20℃., 100 days at 15℃. and 145 days at 10℃. respectively. It is of most interest to observe that, even under the continued influence of such a low temperature as 5℃., the embryos showed significant development attaining to the stage of larval formation at the end of approximately 370 days of incubation, though the development was markedly sluggish and death occurred prior to actual hatching. The data of such observations, if applied to Rough's formula ((v-h)t=K), show that the theoretical developmental zero for the present worm falls on such an astonishingly low point as -1.1℃. Though the applicability of the formula to such lower range of effective temperature as that in the present experiment is wholly problematical, it appears worth of mentioning that the theoretical zero point calculated is lower than that offered by Bodenheimer (1932) with Icerya (developmental zero=0℃.) which has been known as the lowest figure ever reported.
- 社団法人日本動物学会の論文
- 1955-06-15