What causes lightning bugs to luminesce every 15 seconds or so?

I believe it's so that other lightning bugs can find a mate.

	Dio -  889 pts -  (2 years ago)
	I just wonder how two lightning bugs mate?

Yes it is to find a mate. Bioluminescence. =]

"This process occurs in specialized light-emitting organs, usually on a firefly's lower abdomen. The enzyme luciferase acts on luciferin, in the presence of magnesium ions, ATP (adenosene triphosphate), and oxygen to produce light. Genes coding for these substances have been inserted into many different organisms (see Luciferase – Applications). Luciferase is also used in forensics, and the enzyme has medical uses."

- http://en.wikipedia.org/wiki/Firefly#Light_production

Some types of algae (especially during "red tide") also illuminate. =]]

	Peep Bunnies -  1248 pts -  (2 years ago)
	When I saw ATP, I couldn't help but automatically think of photosynthesis. That's what happens when you've been drilled in basic biology throughout middle and high school. >_<

The bugs decide to light up based on seeing a mate.

If the mate lights up, they do as well, and the males use it to find the females on the ground. The females will not light up unless they see a male they think is bright enough.

	god -  4827 pts -  (2 years ago)
	atleast this is as I was told.