Octopaminergic system orchestrates combat and mating behaviors: A potential regulator of alternative male mating tactics in an armed beetle.

Male-male combats over females and territories are widespread across animal taxa. The winner of a combat gains resources, while the loser suffers significant costs (e.g.

Male courtship behavior and weapon trait as indicators of indirect benefit in the bean bug, Riptortus pedestris.

Females prefer male traits that are associated with direct and/or indirect benefits to themselves. Male-male competition also drives evolution of male traits that represent competitive ability. Because female choice and male-male competition rarely act independently, exploring how these two mechanisms interact is necessary for integrative understanding of the evolution of sexually selected traits.

Male aggressive behavior and exaggerated hindlegs of the bean bug Riptortus pedestris.

Males of the bean bug species Riptortus pedestris possess larger hindlegs than females. Observations of male-male interactions showed that the enlarged hindlegs are used as weapons in male fights, and that males with larger hindlegs win fights more frequently. Morphological analysis based on the positive allometry test showed that the femora of larger males are relatively bigger than those of smaller males, but femora of larger females are not relatively larger than those of smaller females.