I was a little worried when buying this because I've read that mosquitos aren't attracted to light and that all these things really do is kill a lot of moths (not that that's not worthy in itself).  However, when I set it up, I was quite pleased to see swarms of mosquitos flying around and into the zapper.  I'm not sure if it's really the light or the octenol scent attracting them, but they are indeed flying into the electric grid and getting zapped.  Perhaps the dominant subspecies of mosquitos in our heavily wooded area of New England is one that likes light.  We live right next to some swampy areas so it seems like there's a neverending supply of mosquitos, but this bug zapper is literally killing thousands of them every night.  I've got to believe that it's making some kind of dent in the local population right around our house.