The insertion of an orientifold $O_{p}$-plane in a string theory setup, results to the following action on the string coordinates $X^{\mu}(\tau,\sigma)$ (leave aside the Chan-Paton factors for now):$$\Omega_{p}X^{i}(\tau,\sigma)\Omega^{-1}_{p}=X^{i}(\tau,\pi-\sigma)$$ and $$\Omega_{p}X^{\alpha}(\tau,\sigma)\Omega^{-1}_{p}=-X^{\alpha}(\tau,\pi-\sigma),$$ where "$i$" are the directions parallel to the orientifold plane and "$\alpha$" the transverse ones.
Now, consider the Green-Schwartz superstring, where we have spacetime supersymmetry. In this case except for the common bosonic $X^{\mu}(\tau,\sigma)$ we have also the fermionic fields: $$\Theta^{I}(\tau,\sigma),\quad \bar{\Theta}^{I}(\tau,\sigma)$$
I am not sure about the action of $\Omega_{p}$ on these fermionic fields. My first thought is that they transform like the bosonic ones but unfortunately I cannot justify it. Is there any justification for the transformation rule or any relevant literature?