Figure 1.

Boxplots of the relationship between relative sperm velocity and male fertilization success in 84 paired-male fertilization trials in Chinook salmon. Relative sperm velocity of the paired males in the focal female’s ovarian fluid significantly explained male fertilization success (pMCMC=<0.001, see Table 2 for MCMCglmm results). Males with a higher sperm velocity than their ‘competitor’ achieved a higher fertilization success. Fertilization success (%) is the proportion of 48 genotyped offspring sired by each male in a paired-male fertilization trial.