Author
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Okuda T; Hodek I
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’˜ŽÒ
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‰œ“c@—²EHodek I
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Title
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Diapause and photoperiodic response in Coccinella septempunctata
brucki Mulsant (Coleoptera: Coccinellidae) in Hokkaido, Japan
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ƒ^ƒCƒgƒ‹
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ƒiƒiƒzƒVƒeƒ“ƒgƒE–kŠC“¹ŒÂ‘ÌŒQ‚ÌŒõŽüŠú‚Æ‹x–°
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Keywords
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Coccinella septempunctata brucki, diapause, photoperiodic response,
Hokkaido
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Abstract
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The regulatory function of photoperiod and temperature on the
life-cycle of Coccinella septempunctata brucki Mulsant in Hokkaido
populations was investigated. Dissection of adults from Sapporo
(43-degrees-N) in mid-October showed diapausing adults (partly hidden in
grass tussocks) possessing enlarged fat body, ovaria without vitellinized
oocytes and at a beginning of regression of testicular follicle tissue.
Some of the females had sperm in their spermathecae. Experimental rearings
under contrasting photoperiods (12L-12D, 16L-8D) and three temperatures
(20, 25 and 30-degrees-C) of insects sampled in early September, and of
their offspring, showed that the Sapporo population has a long-day
photoperiodic response adequate for the induction of winter diapause. This
is in contrast to short-day response inducing summer diapause in the
Nagoya (35-degrees-N) and Kanto (36-degrees-N) plains, but similar to C.
septempunctata septempunctata in France and central and northern Europe,
i.e. regions with climate similar to Hokkaido.
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—vŽ|
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Journal
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Appl.Ent.Zool., 29(4), 1994, p.549-554.
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