| Co-Investigator(Kenkyū-buntansha) |
OSAWA Naoya Kyoto University, Graduate School of Agriculture, Lecturer, 農学研究科, 講師 (10221821)
TSUNO Nobuko Nagasaki Univ., Inst.of Tropical Medicine, Instructor, 熱帯医学研究科, 助手 (60295102)
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| Budget Amount *help |
¥16,000,000 (Direct Cost: ¥16,000,000)
Fiscal Year 2006: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2005: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2004: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2003: ¥8,600,000 (Direct Cost: ¥8,600,000)
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| Research Abstract |
Many large, evolutionarily successful groups of insect owe much of their proliferation to fungal food sources, and fungi frequently profit from insects. However, many fungi produce several kinds of secondary metabolites. And they are often harmful or toxic to insects in general, and may be strongly involved in insect-fungus interaction. The genus Amanita is one of the most famous macrofungal genera of basidiomycetes. They are known to be mainly ectomycorrhizal fungi for several forest trees, and their basdiocarps have been recognized as atypical icon of mushrooms. This genus is also famous to have a spectrum of chemical compounds affecting survival and performance of animals. Amatoxins and ibotenic acid are representative of such compounds found in some Amanita mushrooms. In this study, we focused on the insects, which utilized basidiocarps of Amanita spp, especially A. ibotengutake. The results of the survey over three years indicted that fauna of the insects visiting (feeding) basidi
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ocarps and breeding maggots in them were different. The former consisted of several orders of arthropod, however, the latter was characterized by Diptera, especially only Phorodae and Drosophilidae. The poisons of A. ibotengutake were neurotoxic metabolites ibotenic acid and muscimol, which are non-fatal to mammals but are highly insecticidal. We also studied the effects of these compounds, on egg-to-pupa survival, pupation time, and pupal size in five Drosophila species, D. bizonata (the dominant species of "breeding fauna" in A. ibotengutake basidiocarps), D.angularis, D.brachynephros, D.immigrans, and D.melanogaster. The first three species are mycophagous and use a wide range of mushrooms for breeding, whereas D.immigrans and D.melanogaster are frugivorous. We reared fly larvae on artificial medium with 500,250,125, and 62.5 (μg/ml) of ibotenic acid and/or musimol. The three mycophagous species were not susceptible to ibotenic acid, whereas the two frugivorous species were affected. Less
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