Fraction of optical nuclear activity with respect to the Q_LSS environmental parameter. Low-mass galaxies (10.0 ≤ log (M_⋆) < 10.5 [M_⊙]) are represented by red circles, intermediate-mass galaxies (10.5 ≤ log (M_⋆) < 11.0 [M_⊙]) are represented by orange squares, and high-mass galaxies (11.0 ≤ log (M_⋆) ≤ 11.4 [M_⊙]) are represented by green triangles. The fractions of SFN, optical AGN, and passive SIG galaxies (N_T = 587, 1153, and 559, respectively) are represented from top to bottom in the left panels, and for SDSS single galaxies (N_T = 1777, 3027, and 2063, respectively) in the right panels. The number of galaxies in each Q_LSS bin is shown in tables for each sample at the bottom of each panel. The dashed area in the figures corresponds to the range with common values of Q_LSS between the two samples, from –5.5 to –3.5. Error bars are given considering binomial distribution.