Coevolutionary dynamics in host-parasitoid metapopulation

(1)寄主-寄生蜂系统的寄生率、种群波动和持久性通过改变寄主-寄生蜂系统的寄生行为来考察种群波动和持久性的变化。岛田管理的实验系统。结果表明，寄生率过高，种群波动较大，平均种群规模较小，削弱了系统的持久性。M.Crawley教授和M.Bonsall博士(讲师)应邀来自帝国理工学院，我们就该项目进行了讨论。(2)寄主-寄生系统的共同进化作为寄主-寄生系统种群动态的进化变化，岛田在田间和实验室系统中研究了寄主昆虫和细胞内共生体，Godfray研究了昆虫寄主和病原体系统。基于这些数据，岩泽和佐佐木分析了宿主-寄生虫系统的共同进化博弈。此外，M.Bonsall与M.Tuda(1997年的合作者)合作分析了基于她的数据的共同进化模型。(3)寄主-寄生蜂系统的群落结构研究Godfray针对植物-蚜虫-寄生蜂系统的群落结构，岛田针对豆科植物-Bruchids-寄生蜂群落的数量结构。然后，岛田参观了帝国理工学院，并与Godfray和M.Hassell讨论了这个项目。

(1) Parasitism rate, population fluctuations and persistence in host-parasitoid systemsChange in population fluctuations and the persistence were examined with changing parasitizing behaviors in host-parasitoid systems. Shimada managed experimental systems. Results showed too high parasitizing rate made population fluctuations larger and the mean population size lower, resulting in weaken the system persistence. Prof.M.Crawley and Dr.M.Bonsall (Lecturer) were invited from Imperial College, and we discussed about the project.(2) Coevolution in host-parasitoid systemsAs evolutionary changes in population dynamics of host-parasitoid systems, Shimada studied host insects and intracelluar symbionts in the field and laboratory systems, and Godfray examined insect hosts and pathogen systems. Based on those data, Iwasa and Sasaki analyzed coevolutionary game of host-parasite systems. In addition, M.Bonsall cooperated with M.Tuda (a collaborator in 1997) to analyzed coevolutionary model based on her data.(3) Studies on community structures of host-parasitoid systemGodfray targeted plants-aphids-parasitoids systems and Shimada did legumes-bruchids-parasitoids communities for quantitative community structures. Then, Shimada visited Imperial College and discuss about the project with Godfray and M.Hassell.