Libertia Grandiflora - Flower problem

Hi All,

I have a libertia grandiflora which has alot of buds on it now, but something is eating them at the base of the flower.  There were already slug pellets down so  I don't think it is slugs or snails and I can't see anything when I look at the flowers.  Does anyone have any ideas what this could be?

Any help appreciated.

Sorry for the delay in replying.

The stem looks to be partially eaten through just below the start of the flower bud.  This means that the stem bends and the flower dies off before flowering.

Does that make sense?  If not I'll try and take a photograph...

Thanks for your help.  If it's a bumble bee I won't mind so much!