Part 1: Surveys Shed Light on Georgia Fireflies
By CAITLIN LYONS
The mental picture is clear: stepping outside on a peaceful summer night and seeing flashes of light in the backyard. Whether one believed they were looking at “fireflies” or “lightning bugs,” the excitement was universal, and the phenomenon was unforgettable. As the night grew darker, more lights entered the sky and started to flicker, and even in summer, it felt like Christmas lights were twinkling all around.
This beautiful show is the product of bioluminescence, which is generated from the fireflies’ abdomen by light-producing organs. Our memories may be filled with flashes of yellow, but as the evening progresses, the different species of fireflies begin to emit green and even blue flashes. The adults use displays to attract mates, and for observers with a more trained eye, the variation in displays becomes unmistakable.
Fireflies blink in the growing dark during the survey. (Caitlin Lyons/DNR)
Firefly patterns are diverse: They can vary in location, duration and direction. Depending on the species, fireflies can flash high in the trees, on plants or anywhere in between. The intervals between flashes can range from long to short, and even how long the flash lasts can differ. Some species emit their light as they fly horizontally, others while flying vertically and some when making a loop.
While fireflies may seem plentiful on a warm summer night, they are facing significant threats, and more information is critical to protecting them. DNR conducts firefly surveys to understand this diversity. Georgia is home to over 50 species, more than any other state. The common eastern firefly (Photinus pyralis) is the most abundant, but understanding broader species variation is crucial for their conservation.
For a recent survey on a Monroe farm, DNR wildlife biologist Anna Yellin and her team arrived before sunset, using the daylight to check out the site.
DNR database technician Amaad Blades shows a firefly caught during a survey. (Caitlin Lyons/DNR)
This included exploring the area to find suitable habitat, filling out data sheets and preparing equipment such as nets and red-tinted headlamps. As the sun set and dusk arrived, fireflies started to appear. The common eastern firefly was among the first species to emerge, displaying its striking flash pattern, a j-shaped swoosh. As the evening deepened, the spectacle intensified. Fireflies performed everywhere, some even flying high into the trees, creating an image of sparkling lights against the backdrop of stars.
Once captured by nets, the fireflies were placed into vials, deposited into a cooler and later submerged in alcohol. The goal was to collect two to five specimens of each accessible species. Those out of reach, due to height, were observed but not captured. The fireflies collected are sent to the Xerces Society, a nonprofit focused on protecting endangered invertebrates. Experts at Xerces will run genetic analyses, identify the species through dissection and add the information to the society’s Firefly Atlas, which is used to track data for threatened species.
Apart from the wonder of these nights, the surveys are critical to understanding the diversity and extent of populations in the wake of growing threats. On another survey, the rare Loopy 5 made an appearance, presenting its unique flash pattern. Expanding the knowledge of this species, and others, provides more insight into their status, issues and potential conservation needs.
Habitat loss and light pollution from houses and developed areas are the main threats to these species. Yet, people can take actions to protect fireflies and their habitats.
The surveys DNR and its partners are doing provide a deeper understanding of fireflies, contribute vital information to their conservation and generate an appreciation for the inherent beauty of nature and the wonder of these remarkable invertebrates.
ALSO SEE FIREFLIES PART 2: ‘WE NEED TO KNOW WHAT’S HERE’
Caitlin Lyons is a summer intern with DNR’s Wildlife Resources Division.