  We present a general study of the magnetic excitations within a weak-coupling
five-orbital model relevant to itinerant iron pnictides. As a function of
enhanced electronic correlations, the spin excitations in the symmetry broken
spin-density wave phase evolve from broad low-energy modes in the limit of weak
interactions to sharply dispersing spin wave prevailing to higher energies at
larger interaction strengths. We show how the resulting spin response at high
energies depends qualitatively on the magnitude of the interactions. We also
calculate the magnetic excitations in the nematic phase by including an orbital
splitting, and find a pronounced C_2 symmetric excitation spectrum right above
the transition to long-range magnetic order. Finally, we discuss the C_2 versus
C_4 symmetry of the spin excitations as a function of energy for both the
nematic and the spin-density wave phase.
