2003 Fiscal Year Final Research Report Summary
Effects of pathogens and parasites on wildlife populations
| Project/Area Number |
13480181
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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, Biodiversity Conservation Research Project, Director, 生物多様性研究プロジェクト, プロジェクトリーダー (30108641)
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| Co-Investigator(Kenkyū-buntansha) |
GOKA Koichi National Institute for Environmental Studies, Research Center for Environmental Risk, Team Leader, 化学物質環境リスク研究センター, 室長 (90300847)
NAGATA Hisashi National Institute for Environmental Studies, Biodiversity Conservation Research Project, Researcher, 生物多様性研究プロジェクト, 主任研究員 (00202226)
TAKAMURA Kenzi National Institute for Environmental Studies, Biodiversity Conservation Research Project, Team Leader, 生物多様性研究プロジェクト, 総合研究官 (40163315)
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| Project Period (FY) |
2001 – 2003
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| Keywords | eugregrine / damselfly / mite / bumblebee / warbler / Plasmodium / survival / infection |
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| Research Abstract |
We investigated the relationship between the abundance of mid-gut parasites (eugregarine trophozooites) and the survival of hosts (field-collected damselflies, Mnais costalis) under laboratory conditions. Males of M.costalis are morphologically and behaviorally polymorphic, typically existing as clear-winged nonterritorial sneaks and orange-winged territorial fighters (the latter are larger in size). The survival cost of eugregarine infection for the two morphs was compared. The results suggest that the abundance of eugregarine parasites exerts a substantial cost, which is associated with the maintenance of alternative mating strategies, together with the higher developmental cost and energy expenditure of the fighter morph.
We investigated natural populations of three Japanese native bumblebee species to determine the infection by a tracheal mite, Locustacarus buchneri, which had been detected in introduced commercial colonies of the European bumblebee, Bombus terrestirs. The results indicated that transportation of bumblebee colonies will cause overseas migration of parasitic mites of different origins.
We examined five warbler species (three migratory and two resident) for the prevalence of blood parasites. The blood mears were stained using Giemsa's stain to determine the presence of blood parasites under a microscope with a 100x oil immersed objective. Resident species were found to be less infected than migratory species with Plasmodium sp. This low prevalence of blood parasites possibly due to the lack to suitable insect vectors (e.g., mosquitoes) within Japan, however, the global climate change may cause higher parasite prevalence in resident warbles due to northward shift of vector distributions.
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