Vanessa and the Naked Lady

Today's the day …………………….. for a question

Do you remember the Naked Ladies that I blipped a few weeks back? 

Well I wasn't very keen on them - but I have to say that I've since changed my mind a bit about them.  They are still putting on a very colourful show and when the sun shines, as it did today, they open up and look not too bad, I suppose!  This Red Admiral (Vanessa atalanta)thought so too and spent ages probing with that long tongue.  It ended up covered in pollen on the underside of its wings. 

The strange thing is that - try as I might - I can't find any references to butterflies pollinating these plants.  Can anyone out there in the blip world throw any light on the subject …………………..?