Context :

Aims : Understanding the role of environment in galaxy evolution is an important but still open issue .
In the present work we study the close environment of red and blue L _ { B } \gtrsim L _ { B } ^ { * } galaxies hosted by VVDS-Deep groups .

Methods : We use the VIMOS VLT Deep Survey to study the close environment of galaxies in groups at 0.2 \leq z < 0.95 .
Close neighbours of L _ { B } \gtrsim L _ { B } ^ { * } galaxies ( M _ { B } ^ { e } = M _ { B } +1.1 z \leq - 20 ) are identified with M _ { B } ^ { e } \leq - 18.25 and within a relative distance 5 h ^ { -1 } kpc \leq r _ { p } \leq 100 h ^ { -1 } kpc and relative velocity \Delta v \leq 500 km s ^ { -1 } .
The richness \mathcal { N } of a group is defined as the number of M _ { B } ^ { e } \leq - 18.25 galaxies belonging to that group .
We split our principal sample into red , passive galaxies with NUV - r \geq 4.25 and blue , star-forming galaxies with NUV - r < 4.25 .
We study how the number of close neighbours per L _ { B } \gtrsim L _ { B } ^ { * } galaxy depends on \mathcal { N } , colour , and redshift .

Results : Blue galaxies with a close companion are primarily located in poor groups , while the red ones are in rich groups .
The number of close neighbours per red galaxy increases with \mathcal { N } , \overline { n } _ { red } \propto 0.11 \mathcal { N } , while that of blue galaxies does not depend on \mathcal { N } and is roughly constant .
In addition , these trends are found to be independent of redshift , and only the average \overline { n } _ { blue } evolves , decreasing with cosmic time .

Conclusions : Our results support the following assembly history of L _ { B } \gtrsim L _ { B } ^ { * } galaxies in the group environment : red , massive ( M _ { \star } \sim 10 ^ { 10.8 } M _ { \odot } ) galaxies were formed in/accreted by the dark matter halo of the group at early times ( z \gtrsim 1 ) , therefore their number of neighbours provides a fossil record of the stellar mass assembly of groups , traced by their richness \mathcal { N } .
On the other hand , blue , less massive ( M _ { \star } \sim 10 ^ { 10.2 } M _ { \odot } ) galaxies have recently been accreted by the group potential and are still in their parent dark matter halo , having the same number of neighbours irrespective of \mathcal { N } .
As time goes by , these blue galaxies settle in the group potential and turn red and/or fainter , thus becoming satellite galaxies in the group .
With a toy quenching model , we estimate an infall rate of field galaxies into the group environment of \Re _ { infall } = 0.9 - 1.5 \times 10 ^ { -4 } Mpc ^ { -3 } Gyr ^ { -1 } at z \sim 0.7 .