Science Snippet: Fireflies

In summertime, on a dark night, few of us take the time to ponder the blinking lights of fireflies as they meander around in or near the woods. These little flying lanterns are not flies at all. Rather, they are beetles, a huge group of 400,000 known species, or 40 percent of all insects. Many scientists believe that if all beetle species were known, the number would be closer to a million. Here are some tidbits about fireflies (or “lightning bugs”).

• In the U.S., their carnivorous larvae live in or on the ground feeding on snails, earthworms, or other soft-bodied insects they can grab in their sizeable jaws and stun with a toxic secretion.
• Glowworms are larval fireflies, which may live several years before emerging as adults.
• There are different species of fireflies, and each species has its own pattern of flashing. To draw females close so mating can occur, males use their species-specific flash pattern to attract females of the same species. In some species males synchronize their flashing, which makes for a beautiful deep woods light show.
• The light of fireflies is generated by a chemical reaction between three molecules: luciferin, luciferase, and ATP. Luciferase is an enzyme that accelerates chemical reactions. When it binds to luciferin in the presence of ATP, luciferin produces light. ATP is the chemical energy source for the reaction. The light produces no heat whatsoever.
• Firefly adults exist to mate and ensure survival of the species, and they usually die a week or so after mating.
• Fireflies are poisonous to birds and have a bitter taste.

Next time you are “flashed” by fireflies, enjoy this miracle of nature.

(Lewis, S., 2016, “Silent Sparks: The Wondrous World of Fireflies,” Princeton Univ. Press, 223 pp.)