Weapon performance drives weapon evolution.

Area of Science:

• Evolutionary biology
• Animal behavior
• Sexual selection

Background:

• Sexually selected traits often function as weapons, leading to significant diversity among species.
• The evolutionary drivers of this weapon diversity, particularly the role of combat advantage, remain largely unexplored.

Purpose of the Study:

• To test the fighting-advantage hypothesis for the evolution of weapon diversity in sexually selected traits.
• To investigate how weapon morphology influences combat effectiveness and contributes to diversification.

Main Methods:

• Examined weapon morphology and combat-induced damage in 17 species of coreid bugs.
• Linked specific weapon forms to quantifiable levels of damage inflicted during male-male combat.

Main Results:

• Demonstrated that certain weapon morphologies inflict significantly more damage than others, supporting the fighting-advantage hypothesis.
• Identified a 'weapon performance landscape' with multiple peaks, where diverse weapon forms achieve similar high performance.
• This multi-peak landscape may promote divergent evolution of weapon forms across lineages.

Conclusions:

• Combat advantage is a key factor driving the evolution of diverse sexually selected weapons.
• The multi-peak performance landscape offers a novel explanation for the extensive diversity of weapon forms observed in nature.