Effects of pathogens and parasites on wildlife populations

在实验室条件下，我们研究了中肠寄生虫(真寄生虫)的丰度与寄主(野外采集的蜻蜓)存活的关系。雄性肋骨分枝杆菌在形态和行为上都是多态的，通常以有明确翅膀的非领地潜行动物和橙色翅膀的领海斗士的形式存在(后者体型较大)。比较了两种变异体感染优格列碱的生存成本。研究结果表明，优戈瑞林寄生虫的大量存在带来了相当大的成本，这与维持替代交配策略有关，以及较高的斗蜂形态的开发成本和能量消耗。我们调查了三个日本本土熊蜂物种的自然种群，以确定在引进的欧洲熊蜂商业群体中检测到的一种气管螨布氏蝗虫的感染情况。结果表明，大黄蜂种群的运输会导致不同来源的寄生虫向海外迁徙。我们调查了5种林莺(3种迁徙的和2种留鸟)的血液寄生虫的流行情况。用Giemsa‘s染色在100倍油浸物镜下观察血液中寄生虫的存在。寄居种比迁飞种感染疟原虫较少。血液寄生虫的低流行率可能是由于日本国内缺乏合适的昆虫媒介(如蚊子)，然而，由于媒介分布的北移，全球气候变化可能会导致居民林莺中寄生虫的流行率更高。

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.