Upper panel: relationship between the stellar mass estimated using the Zibetti et al. (2009) mass-to-light colour dependent calibration and the real stellar mass of galaxies in our models of galaxy evolution for unperturbed (red symbols) and ram pressure stripped objects (blue symbols). The dotted line gives the 1:1 relation, while the dashed lines shows a variation of 0.2 dex (this value is typical of the global uncertainties affecting mass determinations due to the choice of the IMF). Lower panel: logarithmic difference between the stellar mass estimated using the Zibetti et al. (2009) mass-to-light colour dependent calibration and the stellar mass from our models for unperturbed (red symbols) and ram pressure stripped objects (blue symbols) is plotted vs. the stellar mass of the model galaxies.