Polyphemus moth

from flickr user CampbellRobert45
Moths have always interested me. I don't particularly approve of them being in my house ever since I had a drawer full of underwear chewed to bits as a child but they are impressive to look at - especially the huge ones. I always wonder why it is that moths exist. Do they, like butterflies, pollinate flowers and feast on nectar or are their actions more on the nefarious side?