Not sure about green aphids. They'd likely have the same gameplay role anyway, and in this case it's about visibility (green aphids vs green plants makes sense in nature, but is undesirable in a game where you're not trying to trick players visually).
As far as ladybug (or ladybird if you're from the UK) predators go... all I can say is that one of our backers, as part of their reward tier, requested them
