The Magic of the Firefly: Why Do Fireflies Glow?

If you grew up in the midwest or south, you probably know these tiny creatures very well, and have always heard them referred to as ‘lightning bugs’. A fitting name for the flashing glow these beetles showcase. So then, just how do fireflies create that magical, illuminating light? As puzzling as it may seem, this phenomenon can be explained by bioluminescence, the ability of a living organism to produce light. The key to this “magic” involves two main chemicals: luciferin and luciferase. When these chemicals interact, they produce light. This chemical reaction also requires oxygen leading some researchers to believe that fireflies regulate their airflow to control the light. Although this chemical process is similar in many species that produce bioluminescence, where exactly the light is produced differs by species. For fireflies, light is made in a region of their abdomen known as the lantern. Fitting right? 

However, only 60 to 75 percent of fireflies produce light; the majority of light producing fireflies reside in Asia and North America. So then, for the fireflies that do produce light, what is the purpose behind this magical ability? According to Sarah Lewis, an evolutionary and behavioral ecologist, it is believed that fireflies developed this ability in the larval or ‘childhood’ stage as a warning to predators that they are toxic. However, when the firefly reaches adulthood, the cause for the flashing lights is more romantic. Lynn Faust, a firefly expert in Tennessee, stated that adult fireflies use their light as a ‘love song’ to attract mates. Adult male fireflies will flash their lights in specific patterns when attempting to attract a female. In response, female fireflies will flash their lights back to let the males know that they have received their signal. 

This romantic exchange is influenced by the fireflies’ primary mating seasons and their preferred climates. Because of this, scientists have raised how the conservation of fireflies is heavily affected by shifting climate patterns and increased light pollution. According to a new collaborative study on this issue, deforestation and increasing dry seasons due to climate change are negatively impacting firefly habitats, and breeding seasons. Alongside this, light pollution caused by an increase of urbanization, or, the process of making space more ‘people’ oriented, interferes with the fireflies’ bioluminescent mating signals. 

The magic of the firefly has, and continues to be, the essence behind many summer memories throughout our lives. Imagining a world without their magic is frightening. In order to preserve these shining lights, we need to do our part in protecting their habitats and pushing back against deforestation. Visit this link to learn more about how you can safeguard these glimmering lanterns so that they can continue to illuminate our summer nights for years to come. 

Resources 

1. Illuminating the facts of deep sea bioluminescence
2. The Illuminating Science Behind Fireflies
3. What’s Behind the Firefly’s Glow | What’s Inside?
4. Fading lights: Multiple threats to North America’s firefly populations
5. How You Can Help | Xerces Society