You can read more about these on my blog here - http://www.craftstorming.com/2012/05/butterfly-swarm-coconut-cupcakes
Step 1: Make the butterflies
Using a butterfly shape cutter cut the wings out of flower paste.
To get the shape give the wings a gentle twist away from you and place them on the corners of cut up cereal boxes to dry.
Shape the bodies out of black gumpaste and fixed on with edible glue.
I love the graduated tones my mum was able to get on these butterflies. She used an airbrush but I think you'd be able to achieve a similar effect painting wth food colours - start with a lighter base colour on the whole wing and then gradually build up with darker colours and different tones towards to edges.