  A constant (spacetime-independent) $q$-field may play a crucial role for the
cancellation of Planck-scale contributions to the gravitating vacuum energy
density. We now show that a small spacetime-dependent perturbation of the
equilibrium $q$-field behaves gravitationally as a pressureless perfect fluid.
This makes the fluctuating part of the $q$-field a candidate for the inferred
dark-matter component of the present universe. For a Planck-scale oscillation
frequency of the $q$-field perturbation, the implication would be that direct
searches for dark-matter particles would remain unsuccessful in the foreseeable
future.
