Email updates

Keep up to date with the latest news and content from BMC Evolutionary Biology and BioMed Central.

Open Access Highly Accessed Research article

Mutualism with sea anemones triggered the adaptive radiation of clownfishes

Glenn Litsios12, Carrie A Sims3, Rafael O Wüest4, Peter B Pearman4, Niklaus E Zimmermann4 and Nicolas Salamin12*

Author Affiliations

1 Department of Ecology and Evolution, Biophore, University of Lausanne, 1015, Lausanne, Switzerland

2 Swiss Institute of Bioinformatics, Génopode, Quartier Sorge, 1015, Lausanne, Switzerland

3 Ecological and Evolutionary Genetics Lab / Coral Reef Ecology Lab, School of Biological Sciences, The University of Queensland, 4072, St Lucia, Australia

4 Landscape Dynamics, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland

For all author emails, please log on.

BMC Evolutionary Biology 2012, 12:212  doi:10.1186/1471-2148-12-212

Published: 2 November 2012

Abstract

Background

Adaptive radiation is the process by which a single ancestral species diversifies into many descendants adapted to exploit a wide range of habitats. The appearance of ecological opportunities, or the colonisation or adaptation to novel ecological resources, has been documented to promote adaptive radiation in many classic examples. Mutualistic interactions allow species to access resources untapped by competitors, but evidence shows that the effect of mutualism on species diversification can greatly vary among mutualistic systems. Here, we test whether the development of obligate mutualism with sea anemones allowed the clownfishes to radiate adaptively across the Indian and western Pacific oceans reef habitats.

Results

We show that clownfishes morphological characters are linked with ecological niches associated with the sea anemones. This pattern is consistent with the ecological speciation hypothesis. Furthermore, the clownfishes show an increase in the rate of species diversification as well as rate of morphological evolution compared to their closest relatives without anemone mutualistic associations.

Conclusions

The effect of mutualism on species diversification has only been studied in a limited number of groups. We present a case of adaptive radiation where mutualistic interaction is the likely key innovation, providing new insights into the mechanisms involved in the buildup of biodiversity. Due to a lack of barriers to dispersal, ecological speciation is rare in marine environments. Particular life-history characteristics of clownfishes likely reinforced reproductive isolation between populations, allowing rapid species diversification.

Keywords:
Ecological speciation; Diversification; Comparative method; Evolutionary rate; Brownian Motion; Pomacentridae