Update

I found an interesting (and timely) article in the NY Times about fireflies. Some facts (in case you're not inclined to click and read yourself):

• There are over 2000 species worldwide
• The larvae glow to warn would-be predators of their bitter taste
  
• Not all adults glow, but for those who do, it is a mating call
• Females can carry on as many as 10 simultaneous conversations and are very picky
• The Photuris firefly kills other fireflies to harvest the bitter chemicals and make themselves even less attractive to predators