AC frequency (log S) per 10⁵   L_⊙ as a function of the absolute V magnitude of the host galaxy (M_V). Open circles show purely old dSph galaxies, while starred symbols indicate galaxies with large intermediate-age populations. The crosses mark the four M 31 satellites, The LMC and SMC are marked by the open triangle (for an assumed luminosity of 2 × 10⁹   L_⊙)³ and square, respectively. The solid line show the fit to the relation for the old systems only, while the dashed line is the fit to the four crosses.