Effects of resource competition and apparent competition on community structure and distributions of drosophilids

资源竞争和表观竞争对果蝇群落结构和分布的影响

基本信息

批准号：
17570010
负责人：
KIMURA Masahito
金额：
$ 2.39万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Competitive interactions between drosophilid species are investigated to understand how drosophilid communities are structured and how the boundary of their distributions, especially at lower latitudes are determined. There are two types of competitive interactions, resource competition and apparent competition mediated by organisms of higher trophic level, such as predators. By laboratory experiments on resource competition, it was suggested that intraspecific competition was rather strong in drosophilid species, but interspecific competition was not so strong. The results of field studies did not contradict with this result. Thus, the effects of resource competition on community structure or distribution seem to be weak. On the other hand, cold-tolerant species are expected to be vulnerable to predators or parasitoids, since their locomotor activity is reduced and their developmental period was prolonged, and therefore they may be excluded from warmer regions due to apparent competition with cold-susceptible species. However, little information is available for apparent competition of drosophilids. Then, the species composition, distribution and host association was studied for parasitoids that are assumed to mediate apparent competition. As a result, all parasitoids were able to parasitize a number of host species. Thus, they could mediate interactions between host drosophilid species. In temperate areas, however, the rate of parasitism was not high and there were a period free from parasitism, suggesting that apparent competition was weak. However, there is a possibility that apparent competition is rather severe in subtropical and tropical areas. Further study is needed on this topic.

研究了果蝇物种之间的竞争相互作用，以了解果蝇社区的结构以及它们的分布边界的结构，尤其是在较低纬度的情况下。有两种类型的竞争互动，资源竞争和由较高营养水平的生物（例如捕食者）介导的明显竞争。通过实验室实验资源竞争，有人提出种内竞争在果蝇物种中相当强，但种间竞争并不那么强烈。现场研究的结果与此结果并不矛盾。因此，资源竞争对社区结构或分布的影响似乎很弱。另一方面，由于它们的运动活性减少并且其发育周期延长，因此预计冷耐耐性物种容易受到捕食者或寄生虫的影响，因此，由于显然与感冒感可感染的物种的竞争，它们可能被排除在较温暖的区域之外。但是，对于果蝇的明显竞争，几乎没有信息。然后，研究了假定介导明显竞争的寄生虫的物种组成，分布和宿主关联。结果，所有寄生虫都能够寄生许多宿主物种。因此，它们可以介导宿主果蝇物种之间的相互作用。然而，在温带地区，寄生的速度不高，没有寄生虫，这表明明显的竞争很弱。但是，在亚热带和热带地区，明显的竞争很可能很严重。需要进一步研究该主题。