“穆氏拟态物种”是有毒的或不好吃的潜在猎物物种，它们与其所模仿的物种并不是密切相关，但却形成了相似的警告色，以遏阻它们共同的捕食者，这种本领是在该过程中通过数量上的优势形成的。在“竞争性排他”有利于一个拟态物种而以其他拟态物种为代价的情况下，不清楚这个效应是否足以维持它们的共存。Martin Taylor及其同事在关于一组物种丰富的热带鲶鱼类群中的“穆氏拟态”的一项研究中研究了这个问题。利用形态测定和稳定同位素分析，他们发现，拟态物种并不占据相同的生境，所以它们并不直接竞争食物，这样便能解释它们的共存能力。（生物谷Bioon.com）
生物谷推荐原文出处：
Nature doi:10.1038/nature09660
Competition and phylogeny determine community structure in Müllerian co-mimics
Markos A. Alexandrou,Claudio Oliveira,Marjorie Maillard,Rona A. R. McGill,Jason Newton,Simon Creer& Martin I. Taylor
Until recently, the study of negative and antagonistic interactions (for example, competition and predation) has dominated our understanding of community structure, maintenance and assembly1. Nevertheless, a recent theoretical model suggests that positive interactions (for example, mutualisms) may counterbalance competition, facilitating long-term coexistence even among ecologically undifferentiated species2. Müllerian mimics are mutualists that share the costs of predator education3 and are therefore ideally suited for the investigation of positive and negative interactions in community dynamics. The sole empirical test of this model in a Müllerian mimetic community supports the prediction that positive interactions outweigh the negative effects of spatial overlap4 (without quantifying resource acquisition). Understanding the role of trophic niche partitioning in facilitating the evolution and stability of Müllerian mimetic communities is now of critical importance, but has yet to be formally investigated. Here we show that resource partitioning and phylogeny determine community structure and outweigh the positive effects of Müllerian mimicry in a species-rich group of neotropical catfishes. From multiple, independent reproductively isolated allopatric communities displaying convergently evolved colour patterns, 92% consist of species that do not compete for resources. Significant differences in phylogenetically conserved traits (snout morphology and body size) were consistently linked to trait-specific resource acquisition. Thus, we report the first evidence, to our knowledge, that competition for trophic resources and phylogeny are pivotal factors in the stable evolution of Müllerian mimicry rings. More generally, our work demonstrates that competition for resources is likely to have a dominant role in the structuring of communities that are simultaneously subject to the effects of both positive and negative interactions.
