M_*-metallicity relation (MZR) in five redshift bins. The solid black lines show the redshift-dependent MZR proposed by Wuyts et al. (2014) in their Eqs. (1) and (2). The predicted metallicity is indicated on the right vertical axis of each plot. The left vertical axis indicates the corresponding [Ν II]λ16584/Ηα flux ratio predicted using the linear calibrations presented in Asplund et al. (2004). Readers can refer to the caption of Fig. 1 for a colour assignment description.