Studies on the sympatric host shift mechanism in monophagous sawflies
| Project/Area Number |
62560043
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | Kobe University |
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Principal Investigator |
NAITO Tikahiko Kobe University, Agriculture, Associate Professor, 農学部, 助教授 (70031226)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1987: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Host race / Host preference gene / Larval survival gene / Disruptive selection / Assortative mating / Mating preference / Conditioning / 寄主特異性 / 生態種(host race) / 産卵誘引物質 / 遺伝的変異性 / 遺伝子流入 / 性フェロモン / 単食性ハバチ / 同所的異質環境 / 奇主植物選択性 / 幼虫可食性 / 同族支配 / 寄主生態種 / 寄主植物選択性 / 幼虫の可食性 / 生殖隔離 |
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| Research Abstract |
1. Sympatric host race formation with host shift is occurring near the southern limit of distribution in the fern sawfly Hemitaxonus japonicus. This is the first discovery that monophagous insects forming host races sympatrically in the field.
2. In the Kii peninsula, the adult host preference and larval survival for two species of ferns, Polystichum tripteron and P. polyblepharum, are remarkably changing in this sawfly within about 10km from north to south near lat. 33ﾟ40'N, where the new host race, polyblepharum race is being formed without geographical isolation. This sawfly is oligophagous south of the zone, while it is divided into two host races, tripteron race and polyblepharum race, north of the zone with reproductive isolation.
3. Adult host preference may be controlled by two alleles at a single locus: A means the tripteron preference allele and A means the polyblepharum allele which is a mutant from A. Larval survival may be also controlled by alleles at a single locus, but the polyblepharum-specific allele might have been derived from the oligophagous allele not by mutation but by conditioning due to oviposition to polyblepharum fern for many generations.
4. Three isolation mechanisms play important roles for sympatric host race formation in this sawfly. Disruptive selection and assortative mating act as a premating isolation and mating preference works as a postmating isolation.
5. Identification of chemical compounds concerned with adult host preference or with mating preference in this species complex is an important problem to solve in future studies.
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Report
(4 results)
Research Products
(17 results)
