The redshift evolution of the average SFR of the BGGs in observations for S-I (black open circle) and for S-II to S-V (black filled circles). The magenta line and the highlighted area represent the best-fitting relation and its 68 per cent confidence intervals. The evolution in the SFR at two given masses (M_S = 10^10.5 and 10¹¹ M_⊙) in the SFR-mass sequence taken from Whitaker et al. (2012) have been shown with dotted and dashed lines, respectively. The average SFR of the BGGs in observations is less than the SFR of the MS galaxies with similar masses in the field and the BGG evolution is different from the MS evolution. The subplot shows the redshift evolution of the mean SFR of the BGGs in the G11 (red diamonds and line) and DLB07 (green squares and line) models, respectively.