iTunes has convinced me that there is a song for just about any topic. When it comes to insects, some are far more popular topics than others. A quick search of iTunes pulls up over 100 hits for songs with “Firefly” in the title.
Fireflies set a romantic mood in the Temptation’s “Firefly”. “Firefly” by Leah Rainy is wistful for summer. Frequently, firefly is used as a metaphor for a “flighty” lover who is uncommitted and playing the field. One of my favorites is the Tony Bennett version of Firefly along with everyone’s favorite, Kermit the Frog:
Living With Insects Blog 
This song “Fireflies” by Owl City is a current popular hit! Its one of my favorite songs…. Although it doesn’t have a LOT to do with the famous beetle that lights up on those perfect summer nights, its a cute song. 😀 Give a listen: http://www.youtube.com/watch?v=psuRGfAaju4
I think the reason so many people enjoy songs about insects such as fireflies is because they usually have no negative connection with them. They usually bring about good memories/feelings. It just wouldn’t bring about the same feeling if hearing a song about a spider or cockroach!
The songs about cockroaches are frequently pejorative comparing other people (often the unfaithful lover) to a cockroach. Spider songs are more mixed. The itsy bitsy spider is a cute kids song.
When I saw the title, I was wondering if it was going to be anything about the sci-fi series called “Firefly”. It was on a long time ago but a lot of fans try to keep the story going. The title comes from the type of ship that is used. It is called a firefly class because it lights up when the engine turns on and the yellow light makes it look like a firefly. http://www.silkandshadows.com/wp-content/uploads/2010/07/firefly-ship-300×225.jpg
If you enjoy sci-fi series and space westerns, I recommend this show.