These fireflies make the forest blink at almost the same rate

In the Great Smoky Mountains, the Photinus carolinus fireflies are known for their synchronized flashes. These are not lamps controlled by an external signal. Insects produce their light through a chemical reaction in the abdomen, with very little heat.

The motif described by the park includes several flashes followed by a dark pause. As more males participate, their rhythms may align. The females respond from the ground, in a light exchange associated with the search for a partner.

The complete reason for this synchronization remains studied; it would be excessive to attribute a single and definitive explanation to it. The dates and intensity of the show also vary with the natural conditions. An isolated flash thus becomes part of a collective signal, striking enough to attract visitors and require measures to protect the site.