Try using ink-blots either actual or via Illustrator to 'draw' insects. Would achieve shades of grey with transparency. Perhaps would build on idea of symbolism and human tendency to find meaning by referencing Rorsach and psychology.
This has to be my favourite, the use of watercolours aren't too much but aren't too little, it gives it an extra pop of colour but makes it blend together. I'd love to do a sort of watercolour flow on the pages of my portfolio.