  We study the evolution of galaxy populations around the spectroscopic WiggleZ
sample of starforming galaxies at 0.25 < z < 0.75 using the photometric catalog
from the Second Red-Sequence Cluster Survey (RCS2). We probe the optical
photometric properties of the net excess neighbor galaxies. The key concept is
that the marker galaxies and their neighbors are located at the same redshift,
providing a sample of galaxies representing a complete census of galaxies in
the neighborhood of star-forming galaxies. The results are compared with those
using the RCS WiggleZ Spare-Fibre (RCS-WSF) sample as markers, representing
galaxies in cluster environments at 0.25 < z < 0.45. By analyzing the stacked
color-color properties of the WiggleZ neighbor galaxies, we find that their
optical colors are not a strong function of indicators of star-forming
activities such as EW([OII]) or GALEX NUV luminoisty of the markers. The
galaxies around the WiggleZ markers exhibit a bimodal distribution on the
color-magnitude diagram, with most of them located in the blue cloud. The
optical galaxy luminosity functions (GLF) of the blue neighbor galaxies have a
faint-end slope \alpha of \sim -1.3, similar to that for galaxies in cluster
environments drawn from the RCS-WSF sample. The faint-end slope of the GLF for
the red neighbors, however, is \sim -0.4, significantly shallower than the \sim
-0.7 found for those in cluster environments. This suggests that the build-up
of the faint-end of the red sequence in cluster environments is in a
significantly more advanced stage than that in the star-forming and lower
galaxy density WiggleZ neighborhoods. We find that the red galaxy fraction
(fred) around the star-forming WiggleZ galaxies has similar values from z \sim
0.3 to z \sim 0.6 with fred \sim 0.28, but drops to fred \sim 0.20 at z >
\sim0.7. This change of fred with redshift suggests that (and more...)
