  We discuss a geometrical formulation for gauge field theories, called
Gauge-Natural, which has been mostly developed at the University of Turin
(Italy) and at the Masaryk University in Brno (Czech Republic). In this
framework, the group of automorphisms of some suitable principal bundle P,
called the structure bundle, acts on fields by means of gauge transformations.
After showing that the classical Wess-Zumino model can be consistently
described within this formalism, we consider minimal supergravity (mSugra). We
find that to embed mSugra in a Gauge-Natural framework, further investigations
are needed. This happens since both the covariance of the Rarita-Schwinger
Lagrangian and the closure of the SUSY algebra occur on-shell.
