EVOLUTION OF CONDITION-DEPENDENT SEX ORNAMENTS AND MATING PREFERENCES: SEXUAL SELECTION BASED ON VIABILITY...

Area of Science:

• Evolutionary Biology
• Genetics
• Behavioral Ecology

Background:

• Previous genetic models indicated that viability alone could not explain the evolution of mate choice and sex ornaments.
• A Fisherian mating advantage was considered necessary for the evolution of traits that reduce survival.

Purpose of the Study:

• To examine if the evolution of mating preferences and secondary sex traits can be based solely on heritable differences in viability.
• To test a genetic model that does not rely on a Fisherian mating advantage.

Main Methods:

• A three-locus genetic model was developed.
• The model assumed a monogamous mating system, precluding a Fisherian mating advantage.
• A key assumption was that ornament development reflects the possessor's condition and genotype.

Main Results:

• Ornament and preference traits can slowly increase in frequency by hitchhiking with alleles conferring a survival advantage.
• This process is contingent on the availability of such survival-advantageous alleles.
• The evolution of mating preferences and secondary sex traits can be driven solely by viability differences.

Conclusions:

• The evolution of mating preferences and secondary sex traits can occur without a Fisherian mating advantage.
• These traits can evolve based on heritable differences in viability, reflecting overall genotypic constitution.
• In reality, viability-based sexual selection may operate in conjunction with other mechanisms.