By Murphy Harrington and Karen Menard

The darkness is aglow with all kinds of “fireworks” this time of year.  In addition to July celebrations-- small beetles, also known as fireflies, add brilliance to our summer light shows with their own, natural bioluminescence.

Shrouded in magic and mystery, fireflies are downright fascinating. But why, actually, do these curious insects flash, and how?

Though not all firefly species flash, those that do most often use their flashes to attract mates. Each species of firefly has its own unique pattern in which the males use to attract females. But that isn’t the only thing firefly flashes are used for. Female fireflies in the Photuris genus mimic other firefly species’ flashes in order to trick males into becoming an evening meal. Other flash-mimics use this tricky skill to reduce mate competition - a clever male mimics the flash of prey and the female approaches only to find a mate, instead of a meal!

The bioluminescent light produced by fireflies is referred to as “cold light” because the reaction used to create it doesn’t produce any heat. Substances such as luciferin, luciferase, and ATP come together to produce the flashes from the firefly abdomen. The energy used to produce this reaction is emitted as light – 100% of it! Compare that to a lightbulb in which only 10% of the energy used is emitted as light.

Unfortunately, these beloved beetles are declining in many areas. Light pollution, pesticide use, habitat degradation and loss, and poor water quality can negatively impact fireflies.  However, by providing no mow areas, reducing the use of bright lighting, planting native species, and varying the heights of trees and shrubs, the habitats in your yard can help to support fireflies. Different species will seek out the tops of taller trees for flash displays and others will utilize low, open areas and vegetation-rich sites for refuge and to easily display their fancy, luminous signals.

Did you know?
There are over 250 firefly species found in North America and approximately 24 species in Ohio. 

For more information about fireflies and how you can help them, please visit www.firefly.org

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Photos: Fireflies (Doug Hinebaugh, Secor); Firefly (right), stock photo.