Evolution of M_dust/M_⋆ as a function of redshift. The gray circle represents the averaged value of local normal galaxies from the sample of da Cunha et al. (2010a), while black solid circles represent the stacking results at z ~1 and z ~2. The light blue and blue solid circles represent “LBG-1” and “Himiko”, which are star-forming galaxies at z = 5.300 and z = 6.595, respectively. The black solid line shows the expected evolution of M_dust/M_⋆ with redshift based on the relation observed in the local universe, M_dust ~ 0.5 × M_gas × Z. Predictions for the redshift-evolution of M_dust/M_⋆ of MS galaxies are shown for the case of an universally valid FMR/broken FMR/evolving M_⋆ − Z relation at z ≥ 3 (red/orange/green lines; the z> 2.5 extrapolations shown in colored dashed lines are observationally-unconstrained). The shaded region shows the range of M_dust/M_⋆ ratio beyond z = 2.5 predicted by our models. All measurements for normal galaxies and predictions have been normalized to a common mass scale of M_⋆ = 5 × 10¹⁰ M_⊙. The star symbols indicate starbursts, same as in Fig. 7. The black dot-dashed line is the best fit to the starbursts with a relation of M_dust/M_⋆ ∝ (1 + z)^{0.51 ± 0.35}.