The dust-to-stellar flux ratio F/F_star after 1 Gyr of dynamical and collisional evolution as a function of the total mass in terrestrial planets, for six wavelengths between 5 and 500 microns. The Spitzer observational limits are shown for 25 and 70 μm with the dashed line (Trilling et al. 2008). In each panel, grey circles represent stable simulations and black circles represent unstable simulations.