Decimator is 'hiding' anatomical elements in renders

NudeFan

I want to use 'Low-Poly-figures' created with the decimator to fill some scenes like a changing room with background figures. I applied a decimation of 80% to a nude G3 male, in details it looks a little scrambled but fine enough for a background figure. This is also valid for the anatomical elements. But when I do a render of this figure, the anatomical elements are gone. What do I have to do to see them also in the renders?

Mod Edit to change thread title slightly to avoid it being misconstrued.