Dust mass as a function of stellar mass for our objects (upper limits) and other related galaxies. The typical uncertainty on M_d due to the unknown dust temperature is about ± 0.4 dex. Strongly lensed galaxies at z ~ 1.5 − 3 from Saintonge et al. (2013) and Sklias et al. (2014), who probed a similar mass range, are shown as black triangles and squares. The blue triangle shows the z = 6.34 starbursting galaxy HFLS3 from Cooray et al. (2014) with M_⋆ adjusted to the Salpeter IMF. Typical uncertainties in stellar masses are a factor 2–3 (cf. Conroy 2013; Sklias et al. 2014), but can be higher in very dusty objects, such as HFLS3 described in Cooray et al. (2014). Dotted, dashed lines: M_d/M_⋆ = 10^-2, 10^-4 (M_⋆ here assumes a Salpeter IMF). The green dashed line shows the location of the sequence observed by the H-ATLAS/GAMA survey at z ~ 0 − 0.35 (Bourne et al. 2012); the green solid line the median value of M_d/M_⋆ = −2.63 obtained by Smith et al. (2012) from the H-ATLAS survey after adjustment to the Salpeter IMF used here. The dust-to-stellar mass ratio of the high-z galaxies studied here is compatible with values observed at lower redshift, down to the nearby Universe.