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Natural Highlights: Big Dipper Firefly

Catching fireflies on warm summer evenings is one of the great pleasures of childhood, and seeing them flash in the darkness is a joy for people of all ages all over the world. There are many species of fireflies, also called lightning bugs, and they can be found on every continent except Antarctica; Tennessee alone has over 25 species.  The firefly species which most of us remember catching as kids and which we see around dusk on summer evenings in suburban yards, is most likely the Big Dipper Firefly (Photinus pyralis), which is widespread and common, a low, slow flyer which starts flashing at dusk in June and July when many people are outside. The Big Dipper males have a relatively long J-shaped flash of about 0.7 second which they use to signal to the females which flash from a stationary position in nearby vegetation. Both males and females have a black spot in the middle of their protonums, the shield-shaped structure just behind the head, which distinguishes them from other species. Big Dippers are tough habitat generalists, able to withstand some of the challenges of an urbanized landscape.  Many people see them in their backyards, especially if they are wildlife-friendly.

You can learn to identify various species by closely observing their characteristic flash patterns and colors which differ from species to species. We highly recommend  the book Fireflies, Glow-worms, and LIghtning Bugs by Lynn Frierson Faust (2017, University of Georgia Press) as a terrific introduction to these fascinating insects.  

Fireflies are one more component of diverse, healthy ecosystems, their absence a sign that their habitat needs are not being met.  Homeowners can do much to create a firefly-friendly yard including reducing excessive outdoor lighting, especially decorative vertical lights into trees (fireflies need darkness to communicate), reducing the use of chemical pesticides and herbicides, encouraging wild corners of habitat, leaving leaf litter and soil undisturbed, using native plants and trees, and providing water.

For more information on fireflies, visit this link:

https://www.sciencefriday.com/educational-resources/talk-like-a-firefly/

Posted by Cathy Justis at 3:35 PM