Fraction of galaxies exhibiting a bimodality in the metallicity distribution of their star cluster population versus stellar mass for disk-(blue) and bulge-dominated (red) galaxies. We show the bimodality when restricting the cluster population to ages τ_c ≥ 2 Gyr (light grey) and τ_c ≥ 8 Gyr (dark grey) in order to compare the results to the ones for the E-MOSAICS simulation from Pfeffer et al. (2023, dotted lines).