Left panel: ratio of H₂ to stellar mass against stellar mass. Virgo SFDs (blue dots) are compared to spiral (grey squares) and irregular-peculiar (red triangles) galaxies from the HRS. Hi-deficient galaxies (Def_HI> 0.5) in both samples are indicated with empty symbols. The dotted line shows the scaling relation obtained for the HRS galaxies with a normal Hi content (Boselli et al. 2014c). Right panel: molecular gas mass fraction against stellar mass. Symbols are the same as in the left panel. Large black squares show the average distribution of the HRS galaxies with a normal Hi content. The dot-dashed lines in both panels indicate the predictions of the model of Lu et al. (2015), and the shaded area corresponds to the uncertainty on the model.