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Competitive environments induce shifts in host fidelity.
1Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden. emma.rova@ebc.uu.se
Journal of Evolutionary Biology
|June 16, 2010
Summary
Frequency-dependent selection in seed beetles did not lead to sympatric speciation. While host fidelity changed, disruptive selection and assortative mating, key speciation factors, did not evolve.
Area of Science:
- Evolutionary Biology
- Speciation Research
Background:
- Sympatric speciation models propose disruptive selection and assortative mating drive divergence.
- Frequency-dependent selection is a proposed mechanism for sympatric speciation.
Purpose of the Study:
- To experimentally test models of sympatric speciation driven by frequency-dependent selection.
- To investigate host fidelity and mating behavior in Callosobruchus maculatus under competitive resource conditions.
Main Methods:
- Utilized experimental evolution with the seed beetle Callosobruchus maculatus.
- Applied high competition on a mixture of resources/hosts to assess behavioral changes.
- Monitored changes in host fidelity and mating patterns.
Main Results:
- Seed beetles evolved more generalistic resource utilization and altered host fidelity.
- Disruptive selection and assortative mating, crucial for sympatric speciation, did not emerge.
- Only one of the three prerequisites for sympatric speciation was observed.
Conclusions:
- Frequency-dependent selection alone, under tested conditions, is insufficient to drive sympatric speciation.
- A shift in resource preference must be coupled with a loss of preference for the ancestral resource for sympatric speciation to occur.
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