  We use properties of the sequences of zeros of certain spaces of analytic
functions in the unit disc $\mathbb D$ to study the question of characterizing
the weighted superposition operators which map one of these spaces into
another. We also prove that for a large class of Banach spaces of analytic
functions in $\mathbb D$, $Y$, we have that if the superposition operator
$S_\varphi $ associated to the entire function $\varphi $ is a bounded operator
from $X$, a certain Banach space of analytic functions in $\mathbb D$, into
$Y$, then the superposition operator $S_{\varphi ^\prime }$ maps $X$ into $Y$.
