Author
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Takeuchi M; Shimizu A; Ishihara A; Tamura M
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著者
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竹内将俊・清水彰宏・石原文子・田村正人
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Title
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Larval diapause induction and termination in a phytophagous lady
beetle, Epilachna admirabilis Crotch (Coleoptera :
Coccinellidae)
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タイトル
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トホシテントウ幼虫の休眠誘起と覚醒
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Keywords
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critical photoperiod, diapause induction, diapause termination,
Epilachna admirabilis, stage sensitive to diapause
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Abstract
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Diapause induction and termination in larvae of a phytophagous lady
beetle, Epilachna admirabilis Crotch, were studied in the laboratory. The
critical photoperiod was approximately 14.7 h. In photoperiodic transfer
experiments between long, and short-daylengths at 24 degrees C to estimate
the beginning and end of diapause sensitivity, we estimated the time
required for 50% diapause by probit analysis to be 2.1 days. The sensitive
period began 6.3 days and ended 12.0 days after molting of 4th-stadium
larvae. As their pupation starts mostly from 12 days after the 4th-stadium
molt under conditions averting diapause caused by long daylength, larvae
of this species are sensitive, and diapause ensues during a later stage of
the 4th stadium. In relation to diapause termination, pupation was
accelerated with increasing duration of cold storage (5 degrees C). Larval
diapause terminated without cold exposure in 33.2 days under long
daylength and 90.6 days under short daylength. These results suggest that
diapause termination and post dispause development are related to
temperature, duration of cold storage, and photoperiod as a token
stimulus.
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要旨
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異なる日長条件下でトホシテントウ幼虫を飼育した結果，臨界日長は14.7hと推定された。幼虫を24℃短日条件と長日条件の間で移行させ，プロビット法を用いて集団の休眠率50％をもたらす時期を調査した結果，休眠を感受するに必要な短日経験日数は2.1日と推定され，休眠感受期は4齢幼虫脱皮後6.3日から12.0日と推定された。一方，休眠覚醒は低温（5℃）にさらされる期間が長いほど促進されたが，60日以上では蛹化までの日数に差異は認められなかった。また低温を経験しなても休眠覚醒が認められ，長日条件下の非休眠4齢幼虫は摂食停止後12.4日で蛹化し，長日条件下と短日条件下におかれた休眠幼虫の摂食停止から蛹化までの日数はそれぞれ33.2日，90.6日で った．以上のことから，本種の休眠覚醒ならびにその後の育は温度，低温の経験期間，日長が関係していることが示唆された。
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Journal
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Appl.Ent.Zool., 34(4), 1999, p.475-479.
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