Lovey-dovey firefly chemistry
STEP 1: For two weeks in early summer, it’s mating season. Females perch on bushes and grass as night falls, awaiting the flashy all-male revue. STEP 2: As the male flies, oxygen enters its bum through tubes in its abdomen called tracheae (A). These run from the exoskeleton surface to light-producing cells known as photocytes. STEP 3: Inside the photocytes, the luciferase enzyme merges with the light-producing luciferin molecule (B), catalyzed by oxygen and energy-storing ATP. The result: oxyluciferin, a compound with excess energy in its atoms that is released as light. It’s visible through transparent segments of the bug’s lower abdomen. STEP 4: The butt of a male firefly undergoes this process every 5.5 seconds. When a guy catches her eye, the female flirts back by flashing her signal about 2 seconds after the male (by means of the same chemical mashup)—a semaphoric wink and blush. STEP 5: The male follows his lady’s light to find her and mate. A few days later, the female lays fertilized eggs in the ground, which hatch two to four weeks later—all thanks to a magical light show.