Hi I have a question concerning the anticommuting variable theta of the superspace manifold: For a proof of some renormalisation theorems I have seen the author make use of the transformation properties of theta under the internal U_R(1) symmetry i.e. he said theta -> exp(-i alpha)*theta ,under this symmetry. Now I would like to know where this comes from. Is it coming from the fact that the SUSY generator Q does not commute with the R-symmetry and that we want theta*Q to be invariant under this symmetry? If so why do we need theta*Q to be invarint? I would really appreciate any response and if my question is not really clear please let me know as well.