Dear Steph: Why do lightning bugs light up? Thanks, Jerry
Good question, Jerry. The flashes are the way that they mate. Males fly around flashing all the time while the women just sort of hang out until they feel like gettin' it on. When she's in the mood, she responds to a nearby male with her own signal.
The flashing itself is caused by bioluminescence which means that a chemical reaction in their bodies causes the light. There are many species of lb's & each one has it's own "code" for flashing to ensure that they only mate within their species.
Good thing humans don't mate like this 'cause I know some ho's whose asses would spontaneously combust!