1998 Fiscal Year Final Research Report Summary
Studies on methods to evaluate the viability of wildlife populations
| Project/Area Number |
08458168
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
環境保全
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| Research Institution | National Institute for Environmental Studies |
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Principal Investigator |
TSUBAKI Yoshitaka National Institute for Environmental Studies, Environmental Biology Division, Deputy Director, 生物圏環境部, 上席研究官 (30108641)
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| Co-Investigator(Kenkyū-buntansha) |
TOMIYAMA Kiyonori Kagoshima University, Faculty of Science, Assistant Professor, 理学部, 助手 (30272107)
NAGATA Hisashi National Institute for Environmental Studies, Global Environment Research Group,, 地球環境研究グループ, 主任研究員 (00202226)
TAKAMURA Kenzi National Institute for Environmental Studies, Global Environment Research Group,, 地球環境研究グループ, 主任研究員 (40163315)
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| Project Period (FY) |
1996 – 1998
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| Keywords | wildlife / genetic variability / fluctuating asymmetry / natural selection / sexual selection / conservation biology / population / viability |
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| Research Abstract |
In the process of population decrease, populations may suffer a significant genetic deterioration, namely a decrease in genetic variability, which may lead to a corresponding decrease in fitness (survival and reproduction). As Fitness can often be measured as fluctuating asymmetry (FA), we analyzed FA in relation to various fitness-related characters, such as survival, growth rate, territoriality and/or reproductive success in several animals. We found negative correlation between mating success and FA in insects including dragonflies, butterflies and midges. FA measurements on several passerine birds revealed that population density and the distribution ranges were negatively correlated with population mean of FA.
Males of the damselfly Mnais costalis (Odonata : Calopterygidae) are morphologically and behaviourally polymorphic, typically existing as clear-winged non-territorial 'sneaks' and orange-winged territorial 'fighters'. The amount of orange pigment in the wing, as measured with a chromameter, varied between individuals and decreased as the reproductive season progressed. Young individuals maintained in the laboratory on high and low nutrient diets differed in the amount of pigment that developed in the wing. Males in the high nutrient group developed darker wings faster than those in the low nutrient group. Young adults of both sexes and morpha were fed ^<14>C radiolabelled tryptophan or tyrosine (precursors of the pigments ommochrome and melanin respectively). Ommochrome was restricted to the pseudopterostigma of the males of both morphs and was not present in females. The presence of tyrosine in the wing cells of orange males but not of clear males indicated that the orange pigment is at least partly constituted from melanin. These data show that at least some pigment levels must be continuously maintained in the wings of orange males, and that maintainance is costly since it is compromised at low nutrient levels.
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