Butterflies appear in art and literature often, as symbols of spring, beauty, transformation, overcoming, freedom, whimsy, and natural change.
The life cycle that takes a creature from lowly caterpillar through the cocoon-state to the beautiful, winged fluttering of a butterfly is no small feat.
As humans enduring our own changes throughout life, we find meaning in the visible, physical changes that transform the caterpillar to butterfly.
Thus the butterfly appears to remind us that change is possible, and even inevitable.