Assessing putative interlocus sexual conflict in Drosophila melanogaster using experimental evolution.

Area of Science:

• Evolutionary Biology
• Behavioral Ecology
• Genetics

Background:

• Sexually antagonistic coevolution theory posits net fitness costs for females due to male interactions.
• Empirical evidence suggests direct costs to female fecundity typically exceed indirect genetic benefits from males.

Purpose of the Study:

• To comprehensively test if females are compensated for direct harm from males through indirect benefits.
• To investigate the selective advantage of a mutation conferring resistance to male costs in Drosophila melanogaster.

Main Methods:

• Experimental evolution using Drosophila melanogaster.
• Introduction of a mutation conferring resistance to male courtship and remating costs.
• Estimation of the selection coefficient for the resistance allele.

Main Results:

• A mutation providing females resistance to male costs, while largely excluding indirect benefits, was strongly favored by selection.
• The estimated selection coefficient favoring the resistance allele was +20%.
• Direct costs of male interactions were not sufficiently counterbalanced by indirect benefits.

Conclusions:

• The findings reinforce the existence of interlocus sexual conflict in Drosophila melanogaster.
• Direct costs imposed by males on females' fitness are substantial and not adequately offset by indirect benefits.
• Female resistance to male harm is a strongly selected trait, highlighting the evolutionary pressures of sexual conflict.