  In this work we compute, at the "one-loop-dressed" level, the nonperturbative
contribution of the ghost loops to the self-energy of the gluon propagator, in
the Landau gauge. This is accomplished within the PT-BFM formalism, which
guarantees the gauge-invariance of the emerging answer. In particular, the
contribution of the ghost-loops is automatically transverse, by virtue of the
QED-like Ward identities satisfied in this framework. Using as nonperturbative
input the available lattice data for the ghost dressing function, we show that
the ghost contributions have a rather sizable effect on the overall shape of
the gluon propagator, both for $d=3,4$. Then, by exploiting a recently
introduced dynamical equation for the effective gluon mass, whose solutions
depend crucially on the characteristics of the gluon propagator at intermediate
energies, we show that if the ghost loops are removed from the gluon propagator
then the gluon mass vanishes. These findings strongly suggest that, at least at
the level of the Schwinger-Dyson equations, the effects of gluons and ghosts
are inextricably connected, and must be combined suitably in order to reproduce
the results obtained in the recent lattice simulations.
