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Alila DO, Ten Brink H, Haesler M, Seehausen O. Ecological character displacement among Nothobranchius annual killifishes in Tanzania. Evolution 2024; 78:679-689. [PMID: 38241699 DOI: 10.1093/evolut/qpae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 12/22/2023] [Accepted: 01/15/2024] [Indexed: 01/21/2024]
Abstract
Divergent ecological character displacement (ECD) is the competition-driven divergence in resource use-related phenotypic traits between coexisting species. It is considered one of the primary drivers of ecological diversification and adaptive radiation. We analyzed phenotypic and ecological variation in 2 African annual killifish species of the genus Nothobranchius: N. eggersi and N. melanospilus in sympatry and N. melanospilus in allopatry. Our aim was to test whether allopatric and sympatric populations of N. melanospilus differ morphologically from each other and from N. eggersi and examine whether these differences are consistent with the predictions of ECD. We find that sympatric N. melanospilus differ from allopatric N. melanospilus and differ from N. eggersi more strongly than the latter. Our data satisfy four criteria for demonstrating ECD: Differences in phenotypes between allopatric and sympatric N. melanospilus are greater than expected by chance; the divergence pattern between allopatric and sympatric N. melanospilus results from an evolutionary shift rather than from ecological sorting; morphological differences observed reflect differences in resource use; and, lastly, sites of allopatry and sympatry do not differ in food resource availability or other ecological conditions. Our results suggest that competition is the main driver of the observed divergence between two N. melanospilus populations.
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Affiliation(s)
- David O Alila
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution, and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
- Division of Aquatic Ecology and Evolution, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland
- Department of Biological Sciences, Mkwawa University College of Education, University of Dar es salaam, Iringa, Tanzania
| | - Hanna Ten Brink
- Division of Aquatic Ecology and Evolution, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland
- Department of Fish Ecology, Royal Netherlands Institute for Sea Research (NIOZ), Texel, The Netherlands
| | - Marcel Haesler
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution, and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
- Division of Aquatic Ecology and Evolution, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland
| | - Ole Seehausen
- Department of Fish Ecology and Evolution, Centre of Ecology, Evolution, and Biogeochemistry, EAWAG Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
- Division of Aquatic Ecology and Evolution, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland
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