We predict new features for the evolution of noncanonical screw wave-front
dislocations nested in diffracting light beams. The evolution equations for
the location of single-charge dislocations are derived, and their conseque
nces are elaborated by use of illustrative examples. It is shown that the d
ynamic trajectories of the vortices can be controlled by adjustment of the
noncanonical strength of the input dislocations. (C) 2001 Optical Society o
f America.