No, I don't know of any great philosophical quotes about the symbolism of a caterpillar turning into a butterfly...sorry.
The only reason I chose a butterfly in my avatar is because when I came here I noticed that some people had animals in their avatars. Over the years I've seen cats, dogs, snakes, (dragons), monkeys, deer, bears, horses, flying squirrels, chickens, lions, birds, scorpions, (Woggle-Bugs), Über-Asmos, and...I think I've also seen owls, saber–toothed tigers, fish, and crows.
So I thought, "Maybe I need to have an animal in my avatar, but what's left, we almost have the whole zoo!?" I just wanted an avatar with a non-threatening, beautiful, colorful animal, you know, not likely to cause anxiety--that's all.
I never stopped to think about those with Lepidopterophobia. No one has that
No one hates butterflies. No one associates butterflies with negative things. Wait, did I just say...
Let me see, what else? I have no butterfly tattoos either. I didn't come here to go through some type of metamorphosis or anything like that either...Wait, I came here as a happy atheist, and I will leave as a slightly angry atheist...so...that might be my metamorphosis right there. Edit
: Just remembered to include chickens, lions, birds, saber–toothed tigers, and a fish.
...And now I have to add beautiful scorpions to the list.
And...a Woggle-Bug and an Über-Asmo --whatever those