Ecological and evolutionary conseguences of diapause in the interactive system between tetranychid mites and their predators
| Project/Area Number |
04660049
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
TAKAFUJI Akio Kyoto Univ., Fac, Agric., Assoc.Prof., 農学部, 助教授 (50026598)
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| Co-Investigator(Kenkyū-buntansha) |
KUNO Eiji Kyoto Univ., Fac.Agric., Prof., 農学部, 教授 (10026560)
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| Project Period (FY) |
1992 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1994: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Diapause / Predator-prey system / Phytoseiid mites / Tetranychid mites / Intraspecific variation / カブリダニ / 遺伝的変異 / 遺伝的変量 / 種内変異 / 捕食者-被捕食者等 |
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| Research Abstract |
We studied the variations in diapause characterisitics in tetranychid mites and their phytoseiid predator, Amblyseius womersleyi, and elucidated the ecological and evolutionary significance of the variations to the interactive system between them.
1. Wide inter-and intra-spesific variations were observed in tetranychid mites, especially in Tetranychus urticae. The diapause of T.urticae was under polygenic control, and its expression was affected greatly by temperature.
2. A.womersleyi had also large variations in diapause intensity. The percentage of diapause showed a latitudinal cline : northern populations showed nearly 100% of diapause at <18ﾟC9L15D,whereas many individuals in populations from Okinawa did not enter diapsue even at 15ﾟC.The diapause expression in populations from intermediate latitudes depended greatly on temperature, and the percentage of diapause decreased with increasing temperature.
3. We studied the relationship between the intensity of diapause and the oviposition
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rate in seveal populations of A.womersleyi. Populations with high intensity of diapause had higher reproductive rates at higher than lower temperatures, whereas the oviposition rate in populations with very weak diapause was not affected by temperature and they had high oviposition rates even at low temperature ranges.
4. We compared the relationship between the diapause characteristics of teranychid mites and A.womersleyi that occurred at the same habitats in intermediate latitudes. Tetranychid mites exhibited wide variations in diapause both between and within species, whereas A.womersleyi showed little variations irrespective of the diapause characteristics of their prey species. Thus, no clear relation was detected, showing that the phenology of the prey species is not the major selective force for determining the diapuse characteristics of the predator.
5. The interactive system between tetranychid and phytoseiid mites often are very unstable. In order that phytoseiid mites maintain their populations, it will be more profitable for the predators to maintain variations in diapause attribute within their populations, than to evolve their diapause strategies strictly in response to the diapause characteristics of their prey. Less
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Report
(4 results)
Research Products
(7 results)
