  Planet migration in protoplanetary discs plays an important role in the
longer term evolution of planetary systems, yet we currently have no direct
observational test to determine if a planet is migrating in its gaseous disc.
We explore the formation and evolution of dust rings - now commonly observed in
protoplanetary discs by ALMA - in the presence of relatively low mass (12-60
Earth masses) migrating planets. Through two dimensional hydrodynamical
simulations using gas and dust we find that the importance of perturbations in
the pressure profile interior and exterior to the planet varies for different
particle sizes. For small sizes a dust enhancement occurs interior to the
planet, whereas it is exterior to it for large particles. The transition
between these two behaviours happens when the dust drift velocity is comparable
to the planet migration velocity. We predict that an observational signature of
a migrating planet consists of a significant outwards shift of an observed
midplane dust ring as the wavelength is increased.
