“Fire-fly, fire-fly! bright little thing,
Light me to bed, and my song I will sing.
Give me your light, as you fly o’er my head,
That I might merrily go to my bed.”
— “Chant to the Fire-fly,” Ojibwe song, 1848
Ah, summer. Each morning the rising sun illuminates our lush world color-splashed with blossoms, blooms, birds…and insects, those oft-maligned creatures that keep our natural world in balance. Think bees. Honey may be a side benefit while their constant pollination is crucial to the production of food. Butterflies with their amazing riot of patterns and hues are not only beautiful, but are also pollinators. Dragonflies are flying jewels, but ferociously control the overpopulation of annoying pests. Workaholic ants may occasionally invade your kitchen, but are necessary for peonies to blossom.
While some are quite useful, such as caterpillars that help us create exquisite silks, wasps beneficial to making ink, others like ticks — lone star, deer or dog — do cause many problems. Yet others, unique in their attributes, have been admired and revered by many cultures over the centuries: lovely ladybugs, chirping crickets and flashing fireflies.
These three, all insectivores, have been collected and cherished by many societies and feature in myth and song, art and jewelry. They may represent knowledge, success, wellbeing, the gospel, the souls of dead warriors, ancestors, romance and love. In Victorian times, an era when true science was emerging, having a firefly (or bat/robin/swallow/owl/gull) in the house meant someone in the family would die soon. Those Victorians were obsessed with death.
Children are captivated by these insects, collect them, keep them as pets and add leaves and grass to the jars with holes in the top to create a bug house. I remember those magically flashing lightning bugs I gathered as a child had to be released the next morning. My parents must have known these little on again/off again glowing beetles were not vegetarians.
So over the glorious Fourth, Danny and I dine out on the patio with family and friends. As the last pale light of the sun dissipates, the shadowy world along the forest and field near us begins to blink and flash with fireflies. This year’s crop is prolific. No matter where you look there are messages being Morse-coded from one insect to another. What are they saying to one another? What does it mean in lightning bug language?
Here in the northeast, two different species flourish at this time of year: Photinus and Photuris, both individual flashers. In Thailand and other parts of the world, some firefly species synchronize their flashes. An entire tree might light up for a few seconds at a time. In the US, Photinus carolinus, a species found in the Great Smokies, has this ability. Every year come June, the Smoky Mountain National Park hosts “The Synchronous Fireflies In The Smoky Mountains.” This is a popular treat. A lottery for tickets is held each year at the end of April/beginning of May.
Entomologists who specialize in fireflies (Are these the curious children who scooped up and studied lightning bugs from an early age?) have delved into the minutiae of why these bugs behave the way they do. Male and female Photinus emit a yellowish light, while Photuris communicate with greenish tinted flashes. Perhaps flashing on and off does not give any firefly predators — bats, birds, mice — time to swoop in and snatch them as a snack.
Once this difference was discovered, scientists determined how often the bugs blinked and what the response time was between male and female. First, the male, the one that is usually on the wing, blinks and, after a few seconds, the female who is often stationary responds. Firefly flirting at its best.
Mysteriously, where the two species roam and play in the same area, the Photuris females, it was noticed, often preyed on the Photinus males. Curiouser and curiouser. One firefly specialist, and there are not many, James E. Lloyd, discovered the two species have different response times. The female Photuris changed her flash response to match that of a Photinus female thus luring the male in — to be eaten.
Whatever for? Another mystery to be solved. In For Love of Insects, Thomas Eisner, an entomologist at Cornell, explains how he and his team went about finding the answer. Eisner had a pet (!) Swainson’s thrush, Phogel, a dedicated insectivore, that liked, disliked or wouldn’t eat certain bugs. Ultimately, this thrush refused three species of fireflies.
What made these so distasteful? Through trial and error, Eisner discovered and named the compound needed in these fireflies to emit light and make them distasteful to predators: lucibufagins. Through meticulous research, it emerged that the Photuris femmes fatales were able to absorb these compounds from the male Photinus by pretending to be a female of his species and eating him. No longer was Ms. Photuris vulnerable to attack; she could successfully breed without fear.
We are mesmerized by the fireflies as they glide hither and thither, glowing so as to appear like mini-comet streaks. A few of these black and orange beetles sit on leaves winking and blinking like tiny, tiny lighthouses. But the femme fatale females are not at all like lighthouses, though. Definitely more like looters swinging lanterns on a cliff on a dark night to lure boats to shore so they could pillage the wreck.
My friend, Philippa, mentions that when her daughter, Sophie, was learning cause and effect — saying “light on/light off” when using a light switch — she used the same analogy when she saw her first lightning bugs: bug on … bug off!