Correlations between sperm characteristics and fertilization success in generalized linear mixed models.

Fertilization success was measured as within-pair (WP) fertilization success (males that had not been cuckolded = 0; males that had been cuckolded = 1), extra-pair (EP) fertilization success (males that had not sired extra-pair offspring = 0; males that had sired extra-pair offspring = 1), and total fertilization success (total number of offspring sired). Red border width and age were added as covariates to the models, but their results are not shown here (see S4 Table).