The Lights of Summer
By Lois Hoffman
The magic appears right after the first of June and lasts for a couple of short months. They bring enchantment to summer nights and the show is free for all, you just have to be still and enjoy. I am talking about lightning bugs, aka fireflies, or whatever you choose to call these small creatures that make a big impact.
Fireworks are special in their own way but, given a choice between the two, I will choose a night spent watching fireflies any day. There is nothing more spectacular than watching them come alive at dusk and lighting up a bean field for as far as the eye can see. How many country kids grew up not catching lightning bugs at night and putting them in jars? There is just something magical here.
Actually, they are not flies at all, but rather beetles, and good beetles at that, compared to many of their cousins. They do not bite nor ravage plants. It is unknown exactly how they got the name “fireflies,” except that the name ‘firebeetles” just doesn’t have the same ring to it.
How fireflies “light up” is intriguing in itself. They are alchemists, creating light as if by magic, except it is not magic at all. Their tails contain two chemicals: luciferase, which is an enzyme that triggers light emission, and luciferin, which is heat resistant but glows under the right conditions. ATP is a chemical that is found in all living beings that converts to energy and, when combined with the first two, it initiates the glow. This glow is bright but not hot to the touch, which is why kids can catch these “night lights” without getting burned.
They are light geniuses because the light produced by a firefly is the most efficient light ever made. Almost 100 percent of the energy in the chemical reaction is emitted as light. In comparison, an incandescent light bulb only emits 10 percent of its energy as light with the other 90 percent being lost as heat.
They definitely have strange diets. The underground larva feast on slimy slugs, grubs, worms, and snails. As they mature, most eat pollen and nectar and some adult species even feast on each other. However, some never eat during their short life span. Can you imagine never eating during your life? But, I guess the world is always in balance because even though they are denied the pleasure of dining as adults, their sole purpose in life is to mate and lay eggs. Even though larva live one to two years, the adult life span is only three to four weeks, long enough to mate and lay eggs.
Not only do they light up our world, but they light up the underworld. Firefly babies emit a subterranean glow and, even stranger, some eggs glow underground. Talk about an eerie sight! They are quite adaptable as some species have gills that allows them to live in the water until they find their way to land for their next phase of life.
They are flashy flirts. Each species has a specific pattern of light flashing and they make use of this pattern to let the ladies of the same species know that they would be a mate. When a female notices a suitable male, she replies with her own species-specific flash. Females also make use of this flash info to decide which male with whom to mate. Nothing like synchronized dating!
Seriously, as if woodlands weren’t made wonderful enough by the firefly’s glittering glow, some species actually synchronize their flashes in a light show. Scientists don’t know why they sync up, but one theory is that it is a competition of males trying to be the first to flash. Or it could be that flashing the species pattern in unison ensures that females notice “their guys” as opposed to males of other species. Their light appears to be white, but the light they emit can actually be a rainbow of colors ranging from yellow, light red, green or orange. The Photinus Carolinus is the only species in America that flashes simultaneously. Such a spectacle that this is, they actually have firefly tours in the Great Smoky Mountains.
A firefly’s natural defense against predators is that they taste disgusting. Their blood contains lucibufagins, a defense steroid that tastes gross. A predator associates the bad taste with light so, naturally, they do not eat bugs that glow. Thus, they have few predators.
In spite of this fact, their numbers are declining due to other factors such as light pollution, pesticide use, and habitat destruction. If something happens to their natural habitat such as a field, they do not migrate, but rather simply disappear forever from that location.
There are some simple things that folks can do to attract fireflies and help make sure that they stick around providing their shows:
• Beware of the pesticides since those that kill other harmful insects also kill fireflies. Lawn chemicals kill their larva.
• Leave snails, worms, slugs and grubs alone as that is the main food supply of the larva.
• Plant flowers and provide other good ground cover such as shrubs, high grass, and some low growing plants since these provide cover and shelter for them. They like moist areas such as wet meadows, forest edges, marshes, wild bogs, stream and lake edges, and farm fields. In some cases where you follow set rules, you can certify your backyard as a wildlife habitat. Check with the National Wildlife Federation for details.
• Dim the lights. They rely on “fire” and when artificial lights like street lights, garden lights, and porch lamps are too bright it confuses them. They respond by being shy and staying away.
• Most of all, resist the urge to catch them and put them in a jar, which usually leads to their demise. The “Firefly Project” was a big factor in this when they paid people to collect fireflies. They paid $12 per ounce or $12 for approximately 600 fireflies. Thankfully, the two chemicals that were sought from their bodies are now produced synthetically.
In diseased cells, the ATP may be abnormal. The chemicals derived from fireflies are injected into these cells and through this, changes in the cells can be detected and used to study many diseases including cancer and muscular dystrophy. Electronic detectors built with these chemicals have been fitted into spacecrafts to detect life in outer space. They have also been used to identify food spoilage and bacterial contamination here on earth.
All in all, these little creatures are fascinating and the world would be a much duller place without them. Few pleasures in life are free and simple. The gifts of the fireflies are. I can’t imagine the summer dusk without the beguiling beauty of their bioluminescence.
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