  Ternary flavor mixtures of ultracold fermionic atoms in an optical lattice
are studied in the case of equal, repulsive on-site interactions U>0. The
corresponding SU(3) invariant Hubbard model is solved numerically exactly
within dynamical mean-field theory using multigrid Hirsch-Fye quantum Monte
Carlo simulations. We establish Mott transitions close to integer filling at
low temperatures and show that the associated signatures in the compressibility
and pair occupancy persist to high temperatures, i.e., should be accessible to
experiments. In addition, we present spectral functions and discuss the
properties of a ``semi-compressible'' state observed for large U near half
filling.
