Number of dwarf candidates as a function of group’s mass. The black and red symbols show the number of candidates with morphological classes less or equal to 2 and 3, respectively. The black error bars show the uncertainty of the numbers: we obtained lower limits by estimating number of the objects whose projected locations are likely overlapping with the group by chance and the upper limits by extrapolating the number of dwarfs for the whole R_vir area in case of partially covered groups. The green line shows the linear fit to the data.