The apple in Twilight represents the forbidden fruit, in their case forbidden love because Bella is human and Edward is a vampire.
New Moon:The bloody tulip according to Stephanie has no meaning and that she didn't pick the image.But I would say the petal falling off represents Edward leaving her and a piece off her missing.
Eclipse:The ribbon represents Bella having to make a choice between her love for Edward and her friendship with Jacob.And she can't decide so the ribbon is tearing.
Breaking Dawn:The red pawn represents bella as a human red cause she's weak warm and blushes alot and the white queen Bella as a vampire it basecly represents her transition into a new life with Edward .
posted over a year ago
the ribbon for eclipse also mostly represents her tearing herself from her human life.