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Parallel evolution of character displacement driven by competitive selection in terrestrial salamanders.
1Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA. dcadams@iastate.edu
BMC Evolutionary Biology
|March 12, 2010
Summary
Interspecific competition drives parallel evolution in salamander head shape across multiple mountains. This ecological character displacement demonstrates how competition can shape species morphology in similar ways across different locations.
Area of Science:
- Evolutionary Biology
- Ecology
- Morphological Evolution
Background:
- Parallel evolution can arise from similar environmental factors or interspecific competition.
- Character displacement, or competitively-driven morphological divergence, can occur when species co-occur geographically.
- Replicated instances of sympatric morphological divergence remain understudied.
Purpose of the Study:
- To test if interspecific competition caused parallel morphological divergence in two salamander species.
- To investigate replicated instances of character displacement across multiple geographic locations.
Main Methods:
- Geometric morphometrics was used to analyze head shape in Plethodon jordani and P. teyahalee.
- Specimens were compared between sympatric and allopatric localities across three distinct mountain transects.
- A novel analytical procedure assessed the consistency of morphological evolution among transects.
Main Results:
- Ecological character displacement was observed in sympatric salamander populations on all three mountains.
- Sympatric specimens exhibited greater cranial differences and increased robustness compared to allopatric ones.
- Morphological evolution within each species was statistically consistent across replicate geographic transects, indicating parallel evolution.
Conclusions:
- The morphological evolution of both species followed a common path across different mountain transects.
- Character displacement likely evolved in situ, suggesting limited dispersal between sympatric locations.
- Competitive interactions are a significant driver of sympatric morphological divergence and parallel evolution between these species.
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