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Spatial and temporal drivers of phenotypic diversity in polymorphic snakes.
Christian L Cox1, Alison R Davis Rabosky
1Department of Biology, University of Texas, Arlington, TX 76010, USA. clcox@virginia.edu
The American Naturalist
|July 16, 2013
Summary
Strong selection drives color polymorphism in ground snakes (Sonora semiannulata) across space and time. This diversity persists despite minimal genetic structure, highlighting complex evolutionary mechanisms.
Area of Science:
- Evolutionary biology
- Population genetics
- Herpetology
Background:
- Color polymorphism is key to understanding phenotypic diversity.
- Polymorphic systems reveal mechanisms of variation distribution.
- The ground snake (Sonora semiannulata) exhibits striking color variation.
Purpose of the Study:
- Investigate evolutionary drivers of color polymorphism in Sonora semiannulata.
- Compare neutral genetic variation with spatial and temporal color variation.
- Examine mechanistic drivers of phenotypic variation across scales.
Main Methods:
- Analyzed neutral genetic variation in ground snake populations.
- Assessed spatial and temporal patterns of color polymorphism.
- Compared morph frequencies across age classes, time, and geographic locations.
Main Results:
- Strong selection promotes color polymorphism across spatial and temporal scales.
- Morph frequencies varied significantly between juvenile and adult snakes.
- Color morph frequencies oscillated over time and varied geographically despite low genetic structure.
- No evidence linked morph conspicuousness to selection or geographic factors like coral snake mimicry.
Conclusions:
- Complex phenotypic variation in polymorphic systems may arise fundamentally from morph conspicuousness.
- Temporal and geographic variation analyses are crucial for interpreting conspicuousness and mimicry.
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