| Project/Area Number |
63480040
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物保護
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| Research Institution | Faculty of Agriculture, Nagoya University |
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Principal Investigator |
ITO Yosiaki Facul.Agr.,Nagoya Univ.Professor, 農学部, 教授 (50115531)
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| Co-Investigator(Kenkyū-buntansha) |
TSUBAKI Yoshitaka Facul.Agr.,Nagoya Univ.Demonstrator, 農学部, 助手 (30108641)
SAKURAI Hironori Facul.Agr.,Gifu Univ.Professor, 農学部, 教授 (50022827)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1989: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1988: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Sterilization / Irradiation / Sperm competition / Melon fly / Electronic microscope / Sperm precedence / Remating suppression / Spermatogenesis |
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| Research Abstract |
Method to count the number of sperm in spermathecae of the melon fly was established, and using this method, it was found that longevity of melon fly sperm in spermathecae is shorter than that of other insects so far known. Due to this short life span of sperm, precedence of last male's sperm for fertilization rise as duration between first and second copulations increases.
Not only copulation with normal (unirradiated) males but also that with sterile (irradiated) males inhibits remating of females. It was shown that copulation with sperm-exhausted sterile males can inhibit remating of females; this is contrasting to case of Drosophila melanogaster, where existence of sperm in spermathecae is necessary to inhibit remating.
Experiments also suggested that the inhibition of remating is a females strategy.
Examinations of testis and spermathecae with an electronic microscope showed that gamma-ray irradiation at a dose which has been used for the melon fly eradication project induce not only dominant lethal mutation in sperm but also physiological and morphological damage to the notable fraction of the sperm; an important result for future development of sterile male technique to eradicate insect pests.
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