Close your eyes and think back to a warm summer night, the smell of a camp fire, roasting marshmallows or eating s’mores; when all of a sudden, a young voice yells out “There one is” and all the kids run to the blinking lights slowly rising into the moonlight sky. We all can remember the endless summer nights as kids, chasing lighting bugs or fireflies after a long day of picnics, swimming, and family gatherings. Even as parents and grandparents, watching kids run to catch their first lighting bug is magical. So what are these blinking summer beacons of joy?
A rose is a rose is a rose, but a firefly is not a fly but a beetle. Scientifically, fireflies are classified under Lampyridae, a family of insects within the beetle order Coleoptera, or winged beetles. There are several thousand species of fireflies that inhabit the temperate and tropical regions of the world. In Ohio there are 25 different firefly species. From glow worms to winter fireflies, there is a species for all seasons. The winter firefly pictured left, is commonly found in maple sap buckets during maple syrup season. Interestingly enough, this firefly does not emit any light. Fireflies inhabit every continent of the world except Antarctica. In North America there are several hundred species, but none west of the middle of Kansas. Not all fireflies emit light or what is called bioluminescence. But in Ohio, the most common type of firefly is Photinus pyralis, commonly known as the “ big dipper firefly” for the J pattern it traces when it lights at night. Another species The Synchronous fireflies (Photinus carolinus) fireflies of the Smokey Mountains have become a huge tourist attraction in recent years. They are the only species in America whose individuals can synchronize their flashing light patterns. They are truly a sight to see.
We all know that a light bulb or any type of light gives off heat and is hot to the touch. So conventional wisdom would expect the light or bioluminescence the firefly produces to give off heat. But no, once again fireflies are very different. The light they produce comes from a complex chemical reaction. Scientists call this “cold light”. The reaction is so efficient that 100% of the energy is emitted as light; compare that to a light bulb where only 10% is emitted as light and 90% as heat. There are several theories about how the firefly turns on and off its “light”, but one thing is for certain, there is a reason for this behavior. As we have seen time and again in nature with colorful feathers, courtship dances, males fighting for dominance, this phenomenon of bioluminescence serves primarily one purpose for the adult firefly….attracting a mate. Both male and female fireflies use their flashing lights to communicate. Some species synchronize their flashes, sometimes across thousands of insects. All species speak a “language of light”.
Unlike people, fireflies love warm, humid weather. It helps them to survive. So in years when summer-like weather arrives before June does, fireflies tend to appear in lawns, gardens, and trees earlier than usual, sometimes as early as late spring. But in Northeast Ohio it is usually June. Fireflies have short life spans. An adult firefly lives only long enough to mate and lay eggs. The verdict is out on what they eat or if they need to eat during their adult life stage. The larvae usually live for approximately one year, from mating season to mating season, before becoming adults and giving birth to the next generation. Firefly larva are primarily carnivorous, usually eating snails and worms. Most firefly larvae are found in rotting wood or other forest litter or on the edges of streams and ponds. Most firefly species have one thing in common: standing water. They live near ponds, streams, marshes, rivers and lakes, but they don’t need a lot of water to get by. Vernal pools …remember them…and small depressions that hold water during firefly mating season can all provide the habitat fireflies need. As any child can tell you, fireflies only come out at night. During the day they spend most of their time on the ground trying to keep cool and avoid the hot sun. At night, they crawl to the tops of blades of grass or weeds and fly into tree branches to signal for mates as well as making childhood memories we keep for a lifetime.
So go out and enjoy a s’more by the camp fire and watch the fireflies do their thing…. God knows at our age we can’t catch them anymore!
