H I vs. stellar mass content of the sources in the NGC 3100 group and of galaxies in different comparison samples. Left panel: H I fraction vs. the stellar mass of the galaxies in the NGC 3100 group (red + blue markers) compared with non-cluster galaxies from VSG+HRS (grey circles, Kreckel et al. 2012; Boselli et al. 2014). Red and blue colours show H I-deficient and normal galaxies, respectively. We show the xGASS scaling relation with a black solid line (Catinella et al. 2018). The black dashed line is the linear extrapolation of this trend for M_⋆  <  1.4  ×  10⁹ M_⊙. Right panel: Similar to the left panel. Here we show the comparison between the H I mass fraction of the galaxies in the NGC 3100 group with that of Virgo cluster galaxies from HRS (light purple circles). Dark purple circles show the average scaling relation obtained from Virgo cluster galaxies (Cortese et al. 2016).