Male traits such as weapon, ornament, and pheromone often have an advantage more in male-male competition for acquisition of females at pre-mating compared males without those. However, in species that a female mate with multiple males, male-male competition to fertilize eggs at post-mating often occurs.

Males with higher moving ability may increase mating success, because they have a potential to increase encounter rate with females. On the other hand, males with lower moving ability may increase resource to post-mating reproductive success, because they have less mating opportunities. Thus, the mating and fertilization success of males may be a trade-off relationship among different moving abilities. To examine this hypothesis, we compared mating success and fertilization success of males between strains with genetically longer (L) and shorter (S) walking distance, in the red flour beetle Tribolium castaneum.

As a result, males of L strains had increased mating success, while males of S strains increased their fertilization success. This result was consistent with our hypothesis. Thus, this study revealed that the mating and fertilization success of males are a trade-off among different moving abilities.