Kaplan Ian, Denno Robert F
Department of Entomology, University of Maryland, College Park, MD, USA.
Ecol Lett. 2007 Oct;10(10):977-94. doi: 10.1111/j.1461-0248.2007.01093.x.
The importance of interspecific competition is a highly controversial and unresolved issue for community ecology in general, and for phytophagous insects in particular. Recent advancements, however, in our understanding of indirect (plant- and enemy-mediated) interactions challenge the historical paradigms of competition. Thus, in the context of this rapidly developing field, we re-evaluate the evidence for interspecific competition in phytophagous insects using a meta-analysis of published studies. Our analysis is specifically designed to test the assumptions underlying traditional competition theory, namely that competitive interactions are symmetrical, necessitate spatial and temporal co-occurrence, and increase in intensity as the density, phylogenetic similarity, and niche overlap of competing species increase. Despite finding frequent evidence for competition, we found very little evidence that plant-feeding insects conform to theoretical predictions for interspecific competition. Interactions were highly asymmetrical, similar in magnitude within vs. between feeding guilds (chewers vs. sap-feeders), and were unaffected by the quantity of resources removed (% defoliation). There was mixed support for the effects of phylogeny, spatial/temporal separation, and the relative strength of intra- vs. interspecific competition. Clearly, a new paradigm that accounts for indirect interactions and facilitation is required to describe how interspecific competition contributes to the organization of phytophagous insect communities, and perhaps to other plant and animal communities as well.
一般而言，种间竞争的重要性在群落生态学中是一个极具争议且尚未解决的问题，对于植食性昆虫来说尤其如此。然而，我们对间接（植物介导和天敌介导）相互作用理解的最新进展对竞争的历史范式提出了挑战。因此，在这个快速发展的领域背景下，我们通过对已发表研究的荟萃分析，重新评估了植食性昆虫种间竞争的证据。我们的分析专门设计用于检验传统竞争理论所基于的假设，即竞争相互作用是对称的，需要空间和时间上的共存，并且随着竞争物种的密度、系统发育相似性和生态位重叠增加，竞争强度也会增加。尽管经常发现竞争的证据，但我们发现几乎没有证据表明植食性昆虫符合种间竞争的理论预测。相互作用高度不对称，在取食类群（咀嚼者与吸食者）内部与之间的强度相似，并且不受去除资源量（落叶百分比）的影响。对于系统发育、空间/时间分离以及种内竞争与种间竞争的相对强度的影响，存在不同的支持证据。显然，需要一个新的范式来解释间接相互作用和促进作用，以描述种间竞争如何影响植食性昆虫群落的组织，也许对其他植物和动物群落也是如此。
