An evolutionary limit to male mating success

Area of Science:

• Evolutionary biology
• Animal behavior
• Genetics

Background:

• Male sexual displays exhibit significant phenotypic diversity and genetic variation, suggesting high evolvability.
• However, empirical evidence demonstrating evolutionary change in male mating success driven by female choice in natural populations is limited.

Purpose of the Study:

• To test the hypothesis that male mating success is highly evolvable in Drosophila bunnanda.
• To investigate the impact of persistent sexual selection on the evolvability of male display traits.

Main Methods:

• An experimental evolution approach was used over 10 generations.
• Populations of Drosophila bunnanda were propagated based on female preference for attractive or unattractive males.
• Male cuticular hydrocarbons (CHCs), the target of female preference, were analyzed.

Main Results:

• Neither the combination of CHCs under sexual selection nor male mating success evolved in response to selection.
• This lack of evolutionary response aligns with previous findings of minimal genetic variance in CHCs for sexual selection in this species.
• Persistent directional selection may deplete genetic variance, imposing evolutionary limits.

Conclusions:

• Male mating success and associated display traits in Drosophila bunnanda are not highly evolvable under the tested conditions.
• Female mate choice, while strong, did not drive evolutionary change due to a lack of underlying genetic variation.
• Erosions of genetic variance by directional selection can limit evolutionary trajectories.