The middle of summer is a great time to see some very cool critters. The long summer evenings bring out so many interesting insects that we don’t find any other time of year. I was thinking about this last night, just before sunset while I was looking into my backyard and watching hundreds of Fireflies or Lightning Bugs blinking in the air of the warm summer evening.
The Firefly is a soft bodied beetle which possesses the remarkable ability to emit light through their body. Fireflies are found in temperate and tropical regions around the world. Although many countries no longer have fireflies. Here in America, they are found in damp forests, wet meadows and other protected areas that have leaf litter covering the ground.
The Fireflies we see at this time of year are a result of adults mating and laying eggs last year. After mating the female lays her eggs either on or just below the surface of the earth. A nice layer of dried tree leaves helps maintain the moisture needed for the eggs to survive. The eggs hatch in two to three weeks and a small larva (tiny worm) emerges. The larva feeds until the end of summer before digging deeper into the soil to overwinter.
In spring the larvae emerge, feeding heavily on snails and slugs for a couple weeks. The larva then pupates (life stage of an insect where it transforms into the adult) for one to two weeks and by the dog days of summer, emerge as the adult beetle. There are more than 2,000 different types or kinds of light-emitting beetles in the world, and each species is slightly different in their lifecycle, light-emitting, and what the adult beetle looks like. Despite their big bright light, our Fireflies are tiny little insects, less than a half of an inch long.
The light production is a chemical process called bioluminescence. It occurs in a specialized organ where an enzyme luciferase acts on luciferin and oxygen and produces light. The oxygen is supplied via the breathing tubes along the abdomen of the beetle’s body. The light they produce is a cold light, no heat energy is produced, making it one of the most efficient light sources. The light has no infrared or ultraviolet frequencies. The light is usually a yellowish color. Different species of Fireflies produce green or pale red colors.
So why do these beetles emit light? Adult beetles emit light for mate selection. In our local Fireflies, both the male and female will blink their bright yellow light on and off. Males are flying around, blinking their light on and off, while the female is on the ground also blinking. This is how they find each other and tell the difference between males and females in the dim light of the evening.
Last night when I was out, I saw a female on the ground (female are slightly larger) and a male was flying nearby. He saw the light and landed within an inch of her. They continued to blink their light on and off. He walked over to her and circled her. I can only assume he is figuring out the lay of the land. When he figured it out, he quickly mounted her, so they were both facing the same direction. This brief encounter will fertilize her eggs, and he flies off to continue blinking and looking for other females. The female goes off to lay her eggs and will die, thus completing the lifecycle of the Firefly.
What I find absolutely fascinating about the Fireflies are, there are fossilized Fireflies dating back 99 million years. This is well back in the dinosaur era. So, when I look out my window and see the flashing of the Fireflies, it feels like I am looking back at ancient times and at the same time looking back at my own youth enjoying a warm summer evening. A childhood without experiencing fireflies in summer is a wasted childhood.Until next time…
Stan Tekiela is an author / naturalist and wildlife photographer who travels the U.S. to study and capture images of wildlife. He can be followed on www.Instagram.com, www.Facebook.com and www.Twitter.com. He can be contacted via his web page at www.NatureSmart.com.
