| Project/Area Number |
06640807
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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 |
生態
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
OHGUSHI Takayuki HOKKAIDO UNIVERSITY,INSTITUTE OF LOW TEMPERATURE SCIENCE,ASSOCIATE PROFESSOR, 低温科学研究所, 助教授 (10203746)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | POPULATION DYNAMICS / SPECIES INTERACTION / PESOURCE DYNAMICS / OVIPOSITION BEHAVIOUR / HERBIVOROUS INSECTS / SPECIES INTERACTIONS |
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| Research Abstract |
An herbivorous lady beetle Epilachna niponica exhibited a high stability of population densities in terms of host plant abundance. Field experments revealed that reproductive females resorbed eggs in the ovary in response to host plant deterioration. Also, females selected oviposition site carefully, by laying eggs on plants with less egg load. These specified oviposition tactics resulted in a temporal resource tracking of populations, through density-dependent reduction in realized eggs per female. Lifetime fitness of offspring decreased with increasing egg density. This implies that oviposition on plants with less egg density improves lifetime reproductive success of an ovipositing female. Egg resorption could have adaptive significance when offspring fitness drops considerably due to resource deterioration late in the reproductive season or habitat disturbance such as inundation. It slso enhances a chance of future oviposition in the second reproductive season, through increasing subsequent survival of egg-resorbed females. Consequently, the oviposition behavior of reproductive females in time and space is highly correlated with lifetime fitness of their offspring.
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