Nature and nurture of early-type dwarf galaxies in low density
  environments
  We study stellar population parameters of a sample of 13 dwarf galaxies
located in poor groups of galaxies using high resolution spectra observed with
VIMOS at the ESO-VLT. LICK-indices were compared with Simple Stellar Population
models to derive ages, metallicities and [alpha/Fe]-ratios. Comparing the
dwarfs with a sample of giant ETGs residing in comparable environments we find
that the dwarfs are on average younger, less metal-rich, and less enhanced in
alpha-elements than giants. Age, Z, and [alpha/Fe] ratios are found to
correlate both with velocity dispersion and with morphology. We also find
possible evidence that low density environment (LDE) dwarfs experienced more
prolonged star formation histories than Coma dwarfs, however, larger samples
are needed to draw firm conclusions.
