Earwigs are active in my garden at the moment and they certainly like petals. So that is a possibility but so are slugs as petals will taste different to the leaves.

I've found lots of little white balls in my viola baskets and have removed numerous little sluggies after noticing that so many flowers were being decimated. I crush the little balls when I find them and I hate to say this, but they make a satisfying crunch. No slime at all. Earwigs? Cor blimey, something else to deter.

the little balls are probably slow release fertilizer if they crack. Sorry Merlinb.d. slug/snail eggs are clear & jelly in nature.