Abstract. We investigate the evolution under the mean curvature flow
of an equivariant Lagrangian sphere. It is shown that under a convexity
assumption on the Ricci curvature, the flow develops a type-II singularity
that rescales to the product of a grim reaper with a flat Lagrangian space.
In particular this result applies to the Whitney sphere. This is joint work
with K. Smoczyk.