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Masaki, Shinzo
概要:
Series of experiments have been carried out with eggs of the Emma field cricket (=Gryllulus mitratus in former publicati
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ons) in order to analyse the effects of temperature in early stages of development on the intensity of diapause, which supervenes at around the time the eggs absorb water. In the first series, batches of pre-diapause eggs were first exposed to different temperatures, respectively, and after the completion of water uptake each batch was further divided and transferred to temperatures of the second exposure for hatching. The results show that the higher the temperature in the first exposure, the longer was the hatching time at each temperature of the second exposure. When pre-diapause eggs had initially been kept at different temperatures and, soon after the onset of diapause, were subjected to cold exposure (6℃), the median effective duration of this treatment for the rupture of diapause was strikingly shorter in those eggs first kept at a low temperature (20℃) than in those kept at a high (30℃). From this it was concluded that the preliminary temperature treatment affects the intensity of diapause. In further experiments, eggs were first exposed to a high temperature for different periods, or for the same period (one week) in different stages, and kept at a low temperature in the remaining stages. From the record of their hatching time, it was suggested that the eggs were responsive to the diapause-intensifying action of high temperature in the late pre-diapause and early diapause stages.
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| 2.
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論文
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Masaki, Shinzo
概要:
A northern (Sapporo) and a southern (Koti) strain of the Emma field cricket (Teleogryllus sp.) were reared for three successive generations in the laboratory, and the characters responsible for the seasonal rhythm of their
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development were investigated. It was found that the embryonic diapause was obligate in both strains, but that the eggs of the northern strain were able to complete diapause at a lower temperature and also in a much shorter time than were those of the southern strain. The rate of post-diapause embryonic and nymphal development was again more rapid in the northern than in the southern strain. The northern adults tended to be smaller in body size than the southern ones, and this difference seemed to be related to their different rates of development. F 1 hybrids obtained by intercrossing of the second generation adults of the two strains were physiologically, as well as morphologically, intermediate between the parent strains, and it was suggested that the polygenes controlling the rate of nymphal development might be located in the autosomes and X-chromosome. From these results it is concluded that in the Emma field cricket the adaptation of the seasonal rhythm of development to local climatic conditions is genetically controlled. The implication of this variability was discussed to a certain extent.
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| 3.
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正木, 進三
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Masaki, Shinzo
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Masaki, Shinzo
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Masaki, Shinzo
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Masaki, Shinzo
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秋月, 観暎
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秋月, 観暎
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秋月, 観暎
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